The possible approaches for VWAT simulation: 1. Cascade model+Leishman-Beddoes dynamic stall model. 2. Double Multiple Stream Tube model. 3. 2D Point vortex +Leishman-Beddoes dynamic stall model+free wake model. 4. Lift line model + +Leishman-Beddoes dynamic stall model+free wake model or vortex in cell method to deal with the complexity of wake. 5. Unsteady free wake Vortex Lattice Method (VLM) or Panel method. 6. CFD methods based on sliding mesh or overset mesh technique and URANS.
Choice of method depends on solidity...for high solidity a relatively simple approach is the cascade model with stall and flow curvature accounted for. CFD - yes, if you have software and a fast comp. Lift line works well - a good example is QBlade.
How about adding a hollow funnel/cone-like structure located below the VAWT? I remember seeing a patent describing it about two decades ago. The patent claims the cone structure would allow to re-focusing the wind/air-flow that coming from opening located on bottom part of the cone, the focused air-flow then used to turn the already spinning VAWT, further increasing its output.
@@rashidisw a university in England just did the math and find if you position the vawts right they are more efficient than the big wind turbines on a large scale. Vawts are the future and the only certified one is the hivawt. This technology has been surpressed by Facebook and the government
Thanks for your comment, if I get a lot of people asking or liking your comment then I will make one! So far there are two of you who want to see more maths 😁😁
@@EngineeringwithRosie I just found this by accident. And probably by TH-cam algorithm secrets... 😉 I would be very, very interested in some more maths behind. I need the for-dummies-version, though. If that is at all possible. Non the less, I think something like this should be on every roof. Even if it's just at 20-30% efficiency with a small battery backup. This could help to keep the fridge running if the power is out for a slightly longer time. And with more and more tech in every home, a small power backup would help save equipment and files by giving people time to shut down their computers, etc. Compared to a horizontal wind turbine, a vertical design is probably much better suited to install on the roofs in an urban environment.
I live in north Texas with constant, powerful wind. I use VAWT exclusively, utilizing both Darrius as well as Savonius designs I have refined over the past 57 years. I am 74. My vawts have completely overcome flutter, stall, vibration, over-speeding problems as well as have zero electrical loading and unloading with wind speed and frequency changes, because one design utilizes 4 moving parts, while another utilizes 2 and ALL my birds compress air into an air grid for storage. Electricity is manufactured in my shop utilizing any of several air-driven engines of my own design. I have several air-driven appliances I have manufactured over the years. Edit: New Sub. I love physics!
Great video !! I'm a retired mechanical engineer and I'm building my dream ranch totally off grid and as much recycled materials as posible. I've built a vawt at my off grid home to suppliment the solar system. I've tried several airfoil shapes and materials most of which have failed. I've studied that vawt are self governing and with our near constant wind here and gusts up to 80mph, that's a plus. At the moment I've settled on 55 gallon drums cut in half as I hope to make this easy and inexpensive to replicate for the Free seminars I plan to give this year. I live in the poorest county in the U.S. and want to give hope to those who have very little and build their self esteem and confidence. We also have outrageous electric costs !! I have a total of $30 invested and my smart drive washing machine alternator/ motor makes 27 volts and 10amps in a 15 mph breeze. All of the design work I owe to the University of U-Tube and thanks for you and everyone sharing your skills to help the world. Charlie
@@RedBatteryHead Hello and thanks for your reply. I used to build nuke plants and high rise buildings in Chicago. I sold my $400,000 dream house,( the greenest house in the state) and moved to northern AZ in 2014. Now that my children are off on their own, I get to live out my dreams of minimalist, self sustainable living. I have community water and power on my lot line but will never tie into it. I refuse to become a consumer !! I'm finishing up a pure hydrogen fuel cell as I received the grapheen last week. I've had good results with HHO but couldn't produce enough to run my car 100% on it and so had to run gas also. The mileage went from 44 to 54 mpg but this new system won't be on demand on the vehicle. I'll make pure hydrogen from my solar powered system and compress it into an old LP tank and use quick air couplers to put into the car and drive away by turning off the gas pump and using it as back up power when the hydrogen runs out. I'll also use it for my back up generator in tandem with solar and windmill power. I can't wait to get up every morning and get to work !! I really appreciate the University of U-Tube as so many great people are sharing ideas. I learn something new every day.
@@RedBatteryHead Thanks for the tip but I'm recycling all I can here and found 250 watt panels for $50 each. I'm trying to repurpose as much as possible as folks here are hanging on by their fingernails and I want them to be able to replicate all I have. I was an electrician in the Marines but mechanical is more my strong suit. I believe I can blunder my way through showing folks how to install a simple system. I'm building a tracking system for mine as I've heard a gain of 30% is possible.
Surely the case for VAWTs should include their advantages at larger scale. This is the "elephants cannot jump" argument. As any structure is scaled up, stresses in that structure increase as the scale, so if you make something twice as big it has eight times the volume and eight times the mass, maybe eight times the cost, and gravitational bending stresses within the structure double. This is a problem for HAWTs, because this increase in stress applies to gravitational bending in the blade roots and this is a fatigue driver and hence a driver of cost of energy LCOE from HAWTs. VAWTS do not suffer this same cyclic fatigue stress and so were thought in the 1980s (when I did my PhD in VAWT aerodynamics) to be destined to replace HAWTs eventually when wind turbines reached large enough scale. (Aerodynamic stresses become less and less important with increased scale.) As it happens we are actually clever enough to make bigger things more expertly and so things including wind turbines do not increase in mass as the cube of linear dimension, but rather mass increases as scale to a power of about 2.2 to 2.6. Amusingly we might remember that body mass index (BMI) is calculated from mass/height^2, not height^3. The effect of this is that gravitational bending stresses do not increase as scale, but they still increase strongly. To combat these increases in stress we hear that more expensive materials (kevlar and carbon fibre) are increasingly used in modern turbines, perhaps to cope with this gravitational edgewise bending fatigue problem. Presumably there will come a time when it will be cost effective to switch to VAWTs?
The scientific answer is unequivocally yes... I spent over ten years as a wind generator turbine and Axial Flux Alternator Design Engineer for the American Energy Research Laboratory. I designed, fabricated and studied many VAWT designs in dynamic environments. VAWTs are uniquely interesting but cannot compete with HAWTs in power generation on physical dimension characteristics. My data indicated the the swept area of a VAWT must be in excess of 4X that of a HAWT to produce a similar output energy production. That was when compared to the most efficient designs available. As an example: A VAWT will require a physical size of +360 sqft swept area (10' X 36') turbine to produce the production of a 10 foot diameter HAWT with 81 sqft of swept area. Both turbines will produce "realistically" approximately 500-1000 watts. Advertisers of wind turbines routinely indicate 2X - 3X more production based upon non-standard values. If you are interested... You can also "guess" the useful output of a generator by weight. Since most "motors" are fabricated using the same components and materials I use a simple rule of thumb. 26 pounds of generator = 742 watts. Once again.... Advertisers claim much much more due to various methods of non-standard calculations. How do I know this? 11 additional years employed as an Engineering Technician for a major motor manufacturing company testing many different motor and generator designs and producing valid data to design engineers producing more efficient products.
@@theosky7162 I do not recommend any VAWT. They are too inefficient for the investment. I recommend a small HAWT to supplement your solar system as part of a hybrid system design. I have attempted many VAWT designs new and old in research for efficiency. None exceeded the three blade common HAWT design. As stated earlier, It takes 4X the swept area of a HAWT to match its output capacity. Unless you are doing hobby research I would not bother. There are hundreds of examples of VAWT deployed designs shut down around the world... Buy a HAWT...
I get the efficiency problem of VAWTs as you have well explained. My question is directed at Generator sources or design class suggestions, as I noted your prior experience as an Alternator Design Engineer. Perhaps I'm still at the 'hobby research' stage, but my intent is to build a multi-input grid-tie system that supplies power to my home, manufacturing shop, and neighbors. As you are surely aware, technology in all the related fields is changing fast now. Solar panels, Battery storage, Wind Turbines, Capacitors, Transformers, Inverters, Hyperbolic collectors, etc... it's a deep dive on all. At the moment I'm concentrating on rotational to electric conversion. Any product compilations for capacity / cost / sources that you know of would be greatly appreciated.
@@theosky7162 I understand...First, let me explain my current build and strategy. I live NW of Amarillo outside any code restrictions. I live 100% off-grid. I have little knowledge of grid-tie systems. I designed, fabricated and distributed a couple of small wind generator APMA's. The designs were sound and extremely reliable but the overseas markets set the retail prices far too low to meet a standard business model. The company was American Energy Research. I sold all the fabrication equipment to Hurricane Wind Power several years ago. Now, the good part! I have built a solar/wind off-grid system to support a 20 acre location on a mesa far enough from Amarillo to not feel the "city" effects. I am still building, or expanding my system. Currently I have 60+ solar panels deployed and another 60 to be installed. These are 24v panels from 225W to 400W. I have upgraded my charge controller/inverter system from PowerJack and MpptSolar to MppSolar models 6048 & 6548 inverters. My system was 24V and upgraded to 48V. I still use GC-2 & GC-8 FLA batteries over 40 of them. I recently purchased (5) 5.2Kw EG-4 server style LiFePo battery packs for storage. Currently I only have one 400W 48V HAWT wind generator to "top-off" my battery storage system. As I mentioned earlier a "hybrid" system is needed in almost all applications. Let me know where your install will be and I can give you a rough idea of the "mix" required to design a working system. Wind is not an issue here as well as sun. I am willing to help you in your quest if I can
Isn’t HAWT not suitable for areas with high turbulent typhoon winds? For potential future 30MW VAWT plant, how many turbine motor generators (of largest commercially available size) would you need at that plant?
Fantastic subject!! Are you ready for more?? Okay, let’s go. Of course I think that VAWT have so many benefits! Coming from Holland and specialized in energy gives near endless options if you live in Canada. Worked with hydraulic windmills horizontally, was in projects to tweak blades. But over all noice and high maintenance on bearings was cause for windmills to be out of service and expensive to maintain. Combined with space (minimal space required for VAWT), noise and added consequences make me aim for vertical. Yes, I see this as best for our future worldwide but we have some development to go through! Welcome in the miracle world, you bring us the future!!
Great Video!! I'm Currently in my final year at university and I'm working on developing the Double Multiple Stream Tube model (DMST) to analyse VAWT turbine performance. So, I'm voting for this for the next video!!! Would love to see your breakdown of it, seen as it's an extension of this video. Or even the single/multiple tube model.
Hey wow, big project. Good luck! You will know more about it than me if you've been researching for a while, I should be asking you for advice! It takes me months to research and finish a new video, so likely you will be finished before I get to it, which means it wouldn't be much help to you unfortunately. I would be interested to see your project though, so please post a link when you're done (and tag me so I get notified).
Yes, I want all the references citations & books. As an Aerospace Engineer with access to CFD codes from my desktop computer, analyzing a number of different VAWT designs is easy. "Cry, Havoc! Let slip the dogs of design", Unfurl the knowledge to the winds, the unexpected will happen. JSW
Floating VAWT have a good future as size can grow but with moving parts closer to ground level they are easier to maintain. For floating, the stability of the VAWT very important and does not require huge engineering and materials like HAWT structures!!
Great presentation! Nice to see someone not treating me like an idiot when explaining something. As I see it, the biggest ADVANTAGE of VAWT is having the "guts" at ground level. The biggest DISADVANTAGE of the Darius-style is that they're not self-starting - but that can be fixed by having a Savonius-style starter turbine.
My take on the VAWTs is that they tend not to chew up a lot of real estate, so, might be more practical for off-grid applications, especially if you need to run multiple turbines due to relatively low efficiencies. I am not an engineer, but I tend to see things from an engineer's point of view. I would like to see a multiple turbine setup using the helical blade design. Another thing that wasn't addressed is the lowest windspeed for practical generation. I envision a hybrid setup with solar as the primary, and wind as the night time/cloudy day backup. Sorry, I have rambled. You gave me a lot to think about, thank you
Hi Rosie! Thank you so much for sharing your well-articulated and super informative videos here on TH-cam. You are a truly inspiring educator. I am a senior wind turbine control systems engineer in the U.S. and have recently been designing the control system and algorithms for a ~100kW H-type VAWT. The turbine has three straight fixed blades, all aluminum. There is no blade pitch mechanism. The lead turbine engineer wants to regulate power in high wind (region 3) via stall regulation by truncating rotor speed past a certain wind speed, thus stalling the blades to prevent increasing torque with increasing wind speed. However, this strategy will generate turbulent flow and potentially damaging vibrations that will lead to early fatigue of the blades and arm connections, as you so eloquently explain in your videos. It is also dicey trying to stall regulate in this fashion because the generator and electronic power converter equipment is required to have sufficient overdesign to handle the surge torque needed to decelerate the rotor in gusty wind in order to keep the rotor in stall. Any slop in the RPM regulation can cause a runaway condition whereby the rotor overspeeds to the point aerodynamic torque exceeds the electrical torque capability of the system, thus the rotor suddenly becomes impossible to decelerate without emergency brakes. The reliance on generator torque to stall the rotor also makes for poor power quality due to electrical torque fluctuations and surges. I have been trying to encourage the design team to consider a future blade pitching approach to simultaneously reduce stall-induced vibrations while also making speed regulation safer and more robust. I'm also concerned with their choice to use aluminum blades, as they will fail sooner, making for a poor quality product and disappointed investors. What are your thoughts? Are you available for consulting? Our company is based in Northern California and our current design prototype is located in the Texas panhandle and is nearly finished. We are commencing initial tests next week.
Hi! Thanks for this comment it is great to hear from someone working on a real-life VAWT project! Your concerns all seem very much in line with the experience of previous VAWT trials. Have you seen this Sandia report? It could help you communicate your concerns to your colleagues. energy.sandia.gov/wp-content/gallery/uploads/SAND2012-0304.pdf I am indeed available for consulting, you can get in touch through my company email rosemary (at) pardaloteconsulting.com
I would share your concerns. A better arrangement to regulate power in high winds is to set the blade angle for as much anti-rotational torque as you can without stalling the blades (and then zero torque), but if you have no ability to change the pitch you are left with the electrical torque that the generator can produce, and as you observe, if this fails, you will get a runaway. To my mind any turbine needs an emergency brake, so it would be better to plan on implementing them from the outset.
Ive recently moved to a windy off grid location and have been wondering about VAWTs to make use of that wind, it seemed so simple to build in that the wind direction doesn't matter but it turns out there's a lot more to it than just the wind direction and length of the blades! Thanks for breaking it down so succinctly!
I would love to see a video detailing the basic mechanical needs and physics of a pitch controlled H-style VAWT. It would be interesting to see how complex it really needs to be. Loved the video!
Hi Rosie! Thank you so much for all of your amazing videos! I started working for a company which supplies composite foams and balsas to LM Wind. Through that I was able to learn about and nerd out over wind turbines and specifically the blades. I'm currently in the Rocky Mountains, USA. I think that locally we could harvest a lot of ancient and modern ideas for green environmental control. For instance I have been really interested in Persian Qanats and ancient evaporative cooling techniques. I've been thinking about, for instance, having a qanat where each wind-catching tower has a VAWT atop it- the fluid dynamics of the qanat help cool interiors while the VAWTS atop a qanat tower might assist with pumping needs or maintenance of the qanat itself! Climate change is sadly irreversible and I neither an engineer nor a prepper but I am really interested in learning how to harness energy in nature to help us all survive in the future. Thank you Rosie for your awesome videos and inspiring content!
I have, over the past 50+ years, overcome ALL of the design limitations of my VAWTs. I use a flat, symmetrical-section vertical "H" design started with a small Savonius rotor at the center. My largest vawt swings a 10-foot arc. I deal with efficiency down on the ground by tweaking how I use the constant energy supply provided by my several turbines. ALL my turbines compress air, and I utilize that stored (in air receivers) potential energy against pistons or pelton-wheel turbines down on the ground, safely inside my shop. I'm 74 years old, and ALL my VAWT towers are counter-balanced, so they fold down easily with just one hand. My tallest turbines are 20 feet tall. I am working towards having 30 VAWTs all compressing air. I store at 120 psig and use automatic condensate drains and check valves on all receivers. I haven't had any mishaps yet and it's been going on 60 years since I started.
@@WhatDadIsUpTo Thank you very much. I am busy building my prototype Savonius. It will be a power takeoff for a pump or compressor or generator. Regards. Hennie Stander
Great video. Shows there are a lot of pitfalls in VAWTm design. I think they have great potential in urban areas without necessarily beating or matching HAWT efficiency...and I'd like to see the maths too
Excellent video. One extra detail for those interested: aircraft wings are also tapered and twisted, for two reasons: 1) To reduce wing tip vortices (drag). 2) To make the outer parts of the wing stall later than the inner parts, to allow control to be maintained to get out of the stall.
Great video, Rosie. One thing I’d be interested to see is your thoughts and calculations on the clustering of VAWTs which I have heard increase their efficiency (unlike HAWTs which are disturbed by nearby turbines).
It would be interesting to make a VAWT with the actuated vanes. Make them out of composite. Put a steel-geared hobby servo at the root of each one with a battery pack. I'll bet with a lithium ion cell or two, that servo could last a long time. Have four vanes in the H-configuration. The base has the generator and a shaft encoder. Maybe have a wind vane and anemometer wired up through the center of rotation to the top. Have the servos control the angle of attack as it spins around, changing for speed and wind direction. Could be fun for a remote camp or mobile off grid situation. Just set it up somewhere and it should start and steer itself. Another idea: figure out some kind of angle of attack "circle" and use some kind of machine learning algorithm that would vary the load and angle of attack profile to maximize power generation, and then have it memorize that "map" for different wind speeds.
I have studied vertical axis turbines and came to the exact same conclusion as you: variable pitch is the answer. The efficiency is so much better. But I needed also to acknowledge: nothing for small, home scale turbines because of the explosive costs.
Nicely done! One potential use for VAWTs, where there may be an improvement over utility-scale HAWTs, is for floating offshore wind. The lower center of gravity significantly reduces the size requirement for the floating platform, potentially reducing the cost of energy. Of course, fatigue is still an issue that must be addressed, and there are a few tricks up our sleeves that might help. The US DOE is funding a program (ATLANTIS) that it includes a VAWT design component.
Hi everybody, I am such a DIY guy and I've started to build more than one VAWT on my backyard. I live in a place with 6m/s medium wind speed / year. So I 've done the math very simplyfied. 1 complete turbine (with generator, charge controler, batteries, inverter, etc) with the cost of materials up to 1000 euros and a medium of 500wh production for only 12 hours/day and 3 years of lifetime will make me save around 3200 euros of energy cost this 3 years. Minus the total costs, it can save around 2000 euros for 3 years. If we combine 2 of them the savings will double, so I can save 4000 euros for 3 years. For only 3 years of lifetime It looks enough efficient for me! In this case I think the low efficiency doesn't matter to much. And don't forget the carbon footprint. Mabe I'm wrong, I'll build it anyway.
There is more effort than in the case of main rotor control mechanism of a helicopter, because: - the wind can come from every direction - each blade must be controlled individually within the whole cycle of revolution. The first idea i had is to use 2 rotor axes separated by half of the blade width from a single axis which can be turned into wind direction. The blades overspan the distance between the axes and are therefore always in the correct angle to the wind, no matter where they are within the cycle of revolution. Maybe, Rosie can comment on this.
Kind of seems like they just need the fastest feedback mechanism and some sort of PID control. There are some DIY projects out there for instance that are used for balancing brushless motors and props, using sensors to tell you exactly where the motor/prop is unbalanced.
To me an actively assisted passive pitch guidance system should be feasible. Put a cam on the central shaft with control rods to the blades. Rotate the cam with wind direction ...
I did a rudimentary vertical axis turbine to pump water for a small village using three sails...like the triangular sails in larger fishing boats. The sails adjust when facing the wind directly as well as when it faces the negative force. It however does need a bit of play on the sail's horizontal beam.
You talked about the drag on VAWT when the blades spin around and essentially move back into the wind but wouldn't the exact same principle apply to HAWT? HAWT's have aerodynamically designed blades to counter this but then couldn't the Horizontal type apply the same? Also from an aesthetic viewpoint (in urban areas) personally I feel VAWT turbines have the edge.
Thanks for the suggestion, I'll add Icewind to my list for future videos. The power in wind depends on wind speed, V, and air density, rho: P=0.5*rho*V^3*A NASA gives data on the Martian atmosphere here: nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html It seems wind speeds are a little lower on Mars than on Earth, but not so low you couldn't use an Earth-designed wind turbine there. A bigger problem is that air density is much lower, only 0.020 kg/m3 compared to 1.225 kg/m3 at sea level on Earth. So there is only one sixtieth of the power available in Martian wind compared to Earth wind (at the same speed).That means you would need a wind turbine sixty times as large to get the same power, and even then you would get less power out of it on Mars than you would on Earth due to the lower average wind speeds. I don't see any reason why you couldn't get a VAWT or HAWT to work on Mars, but it wouldn't be very effective compared to what we're used to on Earth.
@@EngineeringwithRosie Thanks for the reply and data! :) I'm interested in Martian wind power, because every so often a big martian dust storm blows along and cuts off the light for solar. Possibly lasting for weeks. Having a way to keep batteries topped up (using the power of the storm) could be a life saver.. Am I right in thinking that the reduced density/power of the Martian air would make more light-weight turbines viable? Turbines too fragile to last here on earth, could perhaps be mounted on solar arrays to provide a secondary power source. I was picturing something like the Icewind turbine, made from thin aluminium and/or carbon fibre. Apparently, the Icewind's claim to fame is it's ability to operate in light winds. It's not the easiest thing to test at the moment as I'm between spacecraft just now. But I think wind power is being overlooked as a backup power source for a Mars base because of the low air density... Anyway, thanks for the info and all the data driven youtube vids...
Lower wind speed or lower air density does give so smaller forces, but also a corresponding lower power production. So unfortunately you wouldn't see any reduction in the weight of a Martian wind turbine compared to one on earth that produced the same power, except with respect to gravity loads (self weight). I guess your fatigue loads for a horizontal axis turbine at least would be lower, so perhaps you'd save some weight because of that but not a lot.
Well given the success of Ingenuity, and its flights I'm going to consider wind turbine power on Mars as a definite maybe! It seems to show more promise as we learn more, so I'm keeping it on my list of candidates
Anything that can increase the wind speed seen by the turbine in low wind conditions will help, but in high wind, it would be ideal if the funnels could be reversed so that their action helped protect the turbine.
I do think VAWT has its own niche and should not try to compete with HAWT in terms of efficiency. However, we do need to find a way to improve its efficiency as much as we can while still maintaining its advantage over HAWT (omnidirectionality, lower cut-in speed, simpler design, etc). As you have mention in the video, for a distributed, off grid, remote area, and site with lower average wind speed, VAWT is the better choice over HAWT. Finally, i loved your channel and i am glad it popped up in my recommendation algorithm ! Cheers from southeast asia !
I looked into getting a residentially vertical axis windmill and was disappointed that there were so few providers and that I was told to not put it on the roof of my house due to vibrations. Now I understand why, thanks for that
Check out Flower Turbines (flowerturbines.com/). They are a startup in Rotterdam, and will soon be producing turbines in the US, as well. They've patented a few breakthroughs in VAWT technology for residential and urban use.
I have just discovered your channel, sent here by "Just have a Think". I loved your presentation on VAWTs, something I've been interested in for ages. My reason for building one is to supplement my solar for my self sufficient lifestyle, which will include charging my electric vehicle. Most of the time I was watching I was saying to you (pity you couldn't hear me through this one directional medium) "What about an active blade turbine, have you ever heard of one?", and then towards the end you mentioned them. I hadn't heard of them before, except for the one I've designed for myself. I don't have the time or capacity at the moment to build it, however, I hope to do it late this year and early 2022. My biggest concern is the maintenance and wear and tear of the blade angle control system. I believe each blade will be contributing positively for around 300 degrees of the rotation, and I intend to build a 5 bladed version first up. I have built a small cardboard mock up of the blade control mechanism, and as I intend to control the blades with a cam and follower system, I'm also concerned it may be noisy. There will be challenges! But really looking forward to starting that project. I will also be checking out more of your videos.
That sounds like an awesome project! I agree with your assessment of the biggest challenges your design will face, it is good that you know that from the start so you can test out that part of your design first. I will be really interested to see your progress if you feel like sharing on the Engineering with Rosie Facebook or Instagram. Or you can can tag me here too if you make a video.
Maybe you have made this video already but, I would like to see a use case analysis for a vertical wind turbine. Like, say a single family home wanted to install one; how much would it cost and when would the return on investment be?
It would most likely break down before return on investment. And a family home would never get enough power to make any useful difference. Just get solar instead. There is a reason why VAWTs are not used, and the companies that 'reinvent' them go out of business, 100 years after Savonius invented them. You'd think 100 years would be enough for optimization.
I'd love to hear your thoughts on so-called "solid state" wind turbines or if those are just far too new and unproven to have much data/theory on them.
For some reason this got in my recommendations... I'm not really an engineer, more a designer. But I wish I had you as my teacher back in my college days!
Hi Rosie, when designing a VAWT, can one increase rotational speed at the centre (the generator) by placing the two straight blades (in an H design) farther apart? I am referring to a small VAWT for a cottage. I'm hoping to see 200 - 300 watts of power.
- very informative video! I think the Voith Schneider propeller's active pitch control system would make a great system to be adapted for use on VAWTs with active pitch control. Both the direction and the amount of pitch are variable so it would allow efficient operation over a range of tip speed ratios. The system has been used for many years on tug boats and other work boats/ships. I would like your reaction to the VAWT of US Patent #9,494,136. All blades are interconnected forming a stiff structure.
IBM 1130 4K punch cad input I found my copy of the thesis a few years ago and it sparked my interest again. I was simply looking at the torque curve vs the speed ratio. It will rotate to a point and then the torque goes negative so it won't increase in speed. If you add a motor assist to brig the speed ratio over 1 then the torque value continues to increase. That's as far as I got. I never had the computing power to model 3 blades ( or more ). Nor did I try to extract power. I've always wanted to know the limit Betz Law on vertical axis turbines. I've always assumed 3 blades to be the most effective simply because of the accumulation of the sin curves like three phase power but that's not valid. Are more narrow blades more effective than fewer wide blades? Is there an optimum diameter? I just used 3 airfoil designs.
@@RobBCactive All I was able to do was rotate the "wing" in relation to the central axis and then transit around the central axis to find the toque curve. Once you get over a speed ratio of one the wing has a velocity approaching the leading edge. It's the same a foiling in the America's cup down wind.
@@RobBCactive What I did was rather rudimentary. At a low relative velocity the wing going upwind will have a relative velocity of v ( wind ) plus the rotational velocity. The wing going downwind is v ( wind ) minus the rotational velocity. In effect the wing has the trailing edge facing into the wind. In one rotation of the main axis the wing stalls several times. It effectively becomes just a barn door when the wing is perpendicular to the flow. When you get to a speed ratio higher than one then even on the down wind side the wing is seeing the airflow coming to the leading edge. It does however oscillate between a positive lift and negative lift. At low speed ratios it's basically an anemometer. At a speed ratio of one the torque is negative so it won't ever over speed on its own. Once you get to a speed ratio greater than one the torque output increases rapidly. the torque value vs speed ratio is an S curve. The "trick" is to find the optimum wing angle between the radius from the center point to the wing and then angle the wing. That's as far as I got. I never calculated the actual power output. It also means that you have to provide a power input to get to a speed ratio greater than one. It's hard to describe the the effect in words. I's a lot easier to draw a diagram.
are you using maglev to keep the rotator from contacting the stationary part of the vertical axis and creating drag? What about wing fences, either at the ends of the blades, or in the middle, to make the wind more laminar for a longer period of time??
The active blade pitch vertical wing could be achieved more simply on a flat wing with leading and/or trailing flaps / slats (similar to a jet's wing) rather than varying pitch on the whole wing. I think the wing could be made to fly at every point in its rotation by changing it from (relative) concave to convex.
Hi Rosie, I have just discovered your Channel from a referral from "Just Have a Think". You are very knowledgable in the area of aerodynamics (among many other things) and I am wondering if you might have time to explain the way some yachts are able to sail faster than the wind - I'm thinking of those America's Cup yachts sailing in Auckland earlier in the year. How do they sail at 70km/hr when the wind is 15? And what happens to the aerodynamics when they go so fast?
If you are sailing with the wind (wind coming directly from behind you) there is no way you can sail as fast as the wind, the drag of the water is too great. When you are sailing perpendicular to the wind (the wind coming directly sideways to the boat) the canvas takes the shape of a wing, where the lift force of wing is directly forward. Sailboards have less drag on the water than deep hulled boats and can achieve speeds three times the speed of the wind when sailing perpendicular to the wind. Ice boats run on blades (very much like icescates) that reduce drag almost completely, so they are able to achieve speeds 7 times the speed of the wind when sailing perpendicular to the wind. The modern world cup sailboats use hydrfoils to lift the hull out of the water, thereby reducing the drag of the water on the hull. Once you view a sail as a canvas wing, you can fly across the lake and it feels magical. All aircraft and sailboats are based on a tradeoff between lift and drag. Air and water are both considered fluids; so I view wings, sails, and hydrfoils as the same entities. I hope that I was able to answer your question! I find sailing to be exhilarating and get completely separated from the rest of my life when I doing it.
@@bradneubauer4694 you can sail downwind faster than the wind actually! Not directly downwind in a normal sailboat, but perhaps you saw the Blackbird "land yacht" that was all over TH-cam recently? th-cam.com/video/CkhBskovitQ/w-d-xo.html
I covered that a bit in this video: th-cam.com/video/CkhBskovitQ/w-d-xo.html if you look in the description for that one, there are some links on other resources that answer the exact question you're asking.
Give us the math! Also, it would be great to talk about what makes an efficient generator, especially for slower speeds (e.g. low speed wind recovery with vertical axis turbines).
I was wondering the same thing. Isn’t that putting Bernoli’s principal to work? Perhaps use it vertically as in a rocket stove, taking advantage of the thermals created by asphalt in sunlight, for example. The exterior wind channel might also serve as a partial safety cover for the blades of the turbine.
The whole way through I was thinking about changing the blade pitch, except using mechanical means. Probably not as good as doing electronically (as you could then adjust for wind speed as well as direction), but there are some relatively simple mechanisms that could be used at least to increase efficiency, even if it isn't quite maximised.
Dear Rosie Will it be possible for those like me, not too technical, to get from you a blue print to built VAWT? I being looking all over and I was not able to find a trustful source to buid on, thanks.
Hi, I don't know of a resource like that but I will keep an eye out and share with you if I find something. Eventually I plan to make one myself and when I do I can make sure to document so I can supply plans. But that will take a long time (probably minimum a year).
Like many other viewers, I would love to see those math equations Rosie. Also it would be nice if you can tell us about any typical software that is used for those calculus. Thx!!
Man the content is so good! I love the editing, I love your smile and I really like your cursive speaking and cohesion and the confidence you output! First time here so thank you, madam!
Thank you for the practical analysis. We are indeed considering the VAWT for urban Distributed generation and a rural environment where visual and noise aspects need to be minimal. I'll follow with interest any ideas that come up in that respect.
Yes. Because the rotating parts are always in the same areas. HAWTs turn so the blades change locations plus they swing thru the swept area at high speeds which is what gets the birds.
Great content! When talking about pitch variability in VAWTs, a helicopter swash plate comes to mind. The greatest loss in efficiency is likely scale, as the area comparison of presented cross wind between VAWT and HAWT just doesn't compare.
I watched this again in December 2021 and note that a paper was published this month which became available as a preprint about the time you published this presentation. It is based on thesis research by Joachim Hansen under the direction of Dr. Iakovos Tzanakis. What makes it interesting is the analysis of the collective effects of “farms” of VAWTs, with spacing and rotation direction as additional design elements. The citation is Renewable Energy, 2021, vol. 171, issue C, 1371-1381. It may be downloaded at no cost.
HI Rosie, greetings from Colombia. I wonder what is your opinion on ART wind turbines? Is ot worth the trouble? Thanks for your job in communicating this extraordinary world of wind power!
Hi Camilo, thanks for you comment. I don't know ART turbines, and I am just getting hits for paintings of wind turbines when I Google it! Can you share a link so I understand what you mean? Then I will add them to the list for a future video to look in depth at some VAWT designs.
@@EngineeringwithRosie commenting to hear his response, also instead of complexing the mechanics by rotating the blades to solve the negative force area couldn't u just use a one way filter membrane to allow force in the positive direction of the wind and pass-through of wind in the negative force area or u could go more complicated and use a full spherical gyroscope design like nasa uses to test astronauts in a zero spin scenario. Then in the negative area the blades would move up an down cutting the negative wind area space by half and creating a more stable center of gravity under the wind force. I wish I had the means to test both and both together but I don't so I'm just passing along my thoughts 🤔👍
I have a more gerneral question about windturbines. Why are there no ducted windturbines when they are more silent and efficent and why isnt there a impeller version of a ducted Turbine? Is this purly a structural problem?
There's a company called Halcium that is claiming to be developing a ducted WT. It's called Powerpod, but they have very little info out there backing it up. And tbh it has a lot of to-good-to-be-true feelings about it. I think the biggest reason is that wind power depends on the amount of area swept by the blades, which is why industrial HAWTs are made as big as possible, they can sweep a larger area and so capture more power for a given amount of materials (and thus cost). Ducting increases efficiency, but adds material costs, plus limits the size.
Hi Rosie! I love your channel and what you’re doing with it. I accidentally put my comment as a reply to another comment, so it’s a bit buried now. I am interested in wind turbines for off grid applications for small cabins. I will likely install solar systems and the wind turbines will be supplemental to the PV panels. I have not done a formal wind study, but I looking into installing a weather monitoring station to start collecting data. I’ve live on the land for a year and that has shown me that we have gusty winds that are occasionally very strong. There is usually a slight breeze, but I would not classify the land as a high wind location. Thanks so much!! Tom
Thanks Tom, I found your buried comment already. And suggested that you measure wind speed so it seems you are way ahead of me there! Remember to take the wind speed where you want to put the turbine. Near to the ground it will vary a lot from one location to another even close by. Compare your data to published long term data to see how your long term values might look.
@@EngineeringwithRosie Thanks Rosie! I’ll get a weather station and see what I discover. Since I wrote that comment, I’ve been paying more attention to the wind and realize that it’s much stronger and more frequent than I realized. Thanks for responding! 🙏🏻
I loved this piece and have pointed some of our customer at it. We make the Darrius helical turbine you refer to in the video. If ever you want to chat happy to talk.
Good day Rosie, I do have a horizontal axis wind gen on my yacht. The blades regularly stall which causes vibration and then we also have the problem of the yacht rolling and pitching which causes centrifugal forces in all directions. So I was thinking of building a vertical vane. To control the different pitches as the blade is rotating I think a type of leaver system that runs on a cam could be made to control the different angles of attack. The cam can be mounted on the shaft with push rods and a cam follower on the rotating frame.
Another characteristic of VAWTs, that comes to the mind of a laymen, is that they have a smaller footprint. That is in terms of the volume of space around the turbine that needs to be clear of obstructions, in order to allow for the needed rotation. This means that VAWTs seem, to me, to be better suited to urban environments. By this I mean, antennas, guy wires, rooftop water towers, utilities like heating and AC, and so forth, become less of an issue to work around. And, while I was typing this, I thought about you having mentioned that VAWTs are better at dealing with turbulent wind conditions... which are highly prevalent around all of those large and variously shaped buildings.
Hello Rosie, very nice video. I now have a good understanding to what to design for while developing my own VAWT. Can you make a video on which type of airfoil (a lot of different designs available out there) is suitable for developing a 3/4 blade Helical-VAWT. Thanks and Regards.
Here is an airfoil designed for VAWTs. airfoiltools.com/airfoil/details?airfoil=du06-w-200-dt It is very important to scroll down to the Cl/Cl v Alpha graph. The angle of attack is the X axis and the Lift to Drag ratio is the Y axis. The colored lines represent the Reynold number the airfoil is operating at, effected by the speed and the chord (width) of the airfoil. There is a Reynolds number calculator in the top left corner in the Applications section. Based on the graph, a 1.5 meter wide airfoil operating at 10 meters/second would work very well. A 100 mm wide airfoil operating at 5 m/s would be worse than terrible. The characteristic of airfoils to perform poorly at low Reynolds numbers is why small, lift type, VAWTs are not popular.
Please tell what do you think about that types of VAWT: 1) "Round brackets" Darrieus 3-blades rotors 2) Darrieus 3+3 blades rotors with 3 stiffening rings or with one ring + stretch marks (they wrote that such windmills can self-start even in a weak wind without spinning them up with a small Savonius rotor, due to the angle of attack of the blades of 3-4 degrees) 3) One of the most popular for DIY: Ugrinsky-type "paired wings", some of them is simple Novikov's rotor. 4) Lenz2: another most popular for DIY
Great questions, thanks! it's so helpful for me to know which specific designs people are interested in. Can you share a link to sketches of these types, I have not heard most of those terms before.
@@EngineeringwithRosie I don't know why, but TH-cam hides all my comments with links facebook.com/groups/windturbinemakers/permalink/4004016506321339/
@@EngineeringwithRosie Please visit "DIY Wind Turbine Makers" group on the Facebook, and see Daniel Connell's models. TH-cam hides all my comments with links
"Just Have A Think" talked about putting VAWT's in the center margins of busy highways to capture the "waste energy" from passing cars. That would seem to fit the definition of a turbulent flow (opposing flow?) and might help with overall efficiency. The space is usually unused, and any power generated could be used to power roadway lights at night. th-cam.com/video/gcSnwW5v3f8/w-d-xo.html
Hi Rose. I am very excited finding your channel. I also tried to design a VAWT ( Savonius ) with the intention to try and solve the inherent problems like it extract less power , low rotational speed , big stress impulses on the structure , torque variances causing impulses on the drive and generator , torque variances can cause difficult self start , upstream blade exerts a braking force that is lost wind power in the swept area , upstream blade has low pressure at the back of the blade causing drag . Not really good for electricity generation ( According to researchers) . I agree completely with you , you have to add complexity to solve problems. I would like to discuss my design with you . I believe it will solve 90% of all the problems the researchers tell us about. I did build a model for proof of concept .But I need somebody to help me with calculations but confidential because I believe it can be patented . Unfortunately I do not have a big budget , it is a home project .I will appreciate it if you can help. I am Hendrik Stander from Pretoria in South Africa .Regards
We operate a maintenance hangar at a small danish airfield and I am looking into cleaning up our energy sources. Vertical axis wind turbines play a key role (beside our roof suitable for solar panels). The advantages are the possibility to utilise the air flow between two hangars without restricting the use of the area between these hangars too much. Horizontal axis wind turbines are more efficient, but require higher installation which is a problem on airfields. So there are application possibilities despite the lower efficiency.
I'm an MBA, so please forgive any obvious oversights....but what about a Savonius(ish) with partial shrouding? Imagine a shroud looking downwards that would be open 12 to 3 o'clock and 6 to 9 o'clock and shrouded 3 to 6 and 9 to 12 o'clock with a weathervane at 6. The 'intakes' could even be flared to increase the catchment and venturi effect. A simpler alternative would just be a quarter/half shroud at 6-9 to 12 on the advancing scoops. Vertical stacking of smaller HAWTs like a stack of pole mounted V22 Ospreys might be another way to limit lateral dimensions while harvesting more on the vertical. Just spitballing here...lol Love the channel...subbed. Thanks for the teaching.
That's not a silly suggestion at all, there are several designs that use that principle. If I do a follow up video on this topic then I will include some examples of this. Thanks for the comment!
@@EngineeringwithRosie You bet. Looking forward to anything you care to share. I've always been fascinated by all the potential energy around us. Especially in the form of talent. Peace to you, Rosie.
Very interesting Rosie! Umm, so what is a good simple design for a diy VAWT? 4 straight blades with the correct wing shape? 2 blades? 3? I suppose you would want to make the vertical arms holding the blades very strong, maybe add vibration reducing ideas...
Interesting Video, I have applied multi stream analysis to extremely large VAWT with and without pitch control. The approach : For simplicity I have omitted end of blade losses and assumed an average chord length for a constant Re value on an aerofoil at a specific location. The airflow was split into 18 segments matching each 10-degree azimuth locations to calculate loads on the aerofoil at every 5 degrees. At every 10 degrees the aerofoil would be considered as subject to two adjacent airflows. The average tangential force on an aerofoil while in a segment was considered as a quarter of ( Force at start + 2 x Force at mid + Force at end ). To get the power from each segment these average forces were multiplied by the number of blades and tip speed divided by the 36 overall segments. For each segment a Cp is applied to the upstream wind to establish a wind velocity at the aerofoil for an accurate apparent wind velocity and a downstream wind velocity to be used as the upstream velocity on the leeward side. The CL and Cd Values ( taken from Qblade ) dependent on the AOA and Re values are inserted to obtain a true tangential load. The power ( load calculations ) from the segment is compared to the energy extracted from the wind and if the difference is significant: the Cp that was applied is altered. If the Cp had to exceed 59% for the difference in a segment to become insignificant then there are 3 options: Reduce the average chord of the aerofoil. Reduce the number of aerofoils. Reduce the Angle of Attack. The total power output was the sum of all power extracted from the wind in the 36 segments. ( a very small amount bigger than the calculated power from each segment due to +ve differences ) With Controlled AOA of 16 degrees on windward side and 12 degrees on leeward side The AOA was 0 between 355 to 5 degrees and 175 to 185 degrees I noted that I had to reduce the AOA on the leeward side to bring the CP down to 59% in several segments. The method of pitch control is based on aerodynamic balance eliminating the need for any servos. The pitch constantly changes to maintain the specified AOA for the windward and leeward sides. To minimise end of blade losses ( which I had ignore ) : Are there any equations that take winglets into account? Has Splitting the end of a foil into 2 close parallel sections to create a central parallel flow been considered? It is interesting to note that the AOA could be increased in the 180-to-270-degree quadrant slightly but the simplified cam-controlled and aerodynamic balancing system for the AOA increases the power by slightly more than 11 % compared to fixed aerofoils. The non pitching result was very similar to that indicated by the power using Qblade. Happy to share the spread sheet with those interested. Leave a request in the comments on maxwindpower.com
Hi Thank you for the video. I have two naive questions. The first question is whether you have rethought vawt for turbine farms given the recently published article on how (if I understand it correctly) hawt farms cause turbulence which lowers the overall efficiency? The second question is why not place blades perpendicular to the circumference of the turbine? Then they will be a little like a sailboat. (For simplicity sake I am assuming four blades with 90 degree separation), when the wind is coming from behind the vawt beyond 6:00, the first blade at 6:00 (the closest) will get lift in the direction that part of the circumference is moving, the second blade at 3:00 will be pushed like a sailboat with the wind, the third blade at 12:00 will get lift in the direction that part of the circumference is moving, and the last blade will either be total drag, or its angle will be adjusted so it cuts through the wind rather than acting as a drag? Thanks Phil Troy
The first question: no need to rethink. That research has been somewhat misrepresented in mainstream media reporting. Wind energy engineers already knew there is decreased wind speed and increased turbulence downstream of a wind turbine. Your second question I don't really understand sorry!
Very nice video ! Usually so many people say anything about wind turbines, especially for VAWT ! To my point of view, the best compromise for a VAWT is a Darieus twisted mode (twisted for a more constant torque as you mentionned). I worked ten years ago of such project. It was so exiting to play with aera (and CFD), structure (FEM) and electrotech to control the speed (and the power). May be you should notice this point for VAWT. Without furling and pitch for twisted, regulation can just be done by a controler on the TSR (to reduce efficiency)
Hi @Engineering with Rosie, I have an unusual request: how do you figure out the VAWT efficiencies of one where the vertical axis is a solid cylinder, instead of being hollow? In particular, I’m thinking a very large diameter vertical axis compared to the size of the blades, with a rather large building in mind, and I do wonder if the diameter getting notably larger will result in gross inefficiencies for wind harvesting due to a lot of overlap. I’ve been working on a radical city concept that emphasizes system efficiency in economies of scale for size, and one of the observations I’ve made is when scale is done correctly, even if a smaller scale version wouldn’t be very efficient, if you can go huge, and integrate it as part of a larger overall ecosystem, energy usage can be greatly reduced, in a geometrically-related way. Thanks!
@@EngineeringwithRosie I’m no graphics artist, I’m a computer geek by trade. So, perhaps you can visualize what’s needed with this description: for the VAWT, I’m looking at about a mile in diameter, and a similar manner of concentrating wind as used for a Tesla Turbine, with collector holes all the way around. The height would be perhaps about one story in height. The objective is to use the same principle as a Tesla Turbine, using the viscosity of the air to drag it along: the thickness of the “blades” would be optimized for the surface boundary effects in the same manner as a Tesla turbine. This sort of VAWT would be part of the top story of a large building that’s ideally not directly on the ground. The big question to answer is if this can be made to work using the same principles as the Tesla turbine efficiently enough to be cost-effective. There’a no need for energy capture to be maximally-efficient, and a HAWT peaks out about 59% in theory. If something can work that’s more readily maintained, doesn’t create too much noise, and has a safe failure mode and what’s more, is part of a building already there (this city would be a lattice of giant 1 mile diameter octagons and intermeshing squares, about 500 feet wide for the edges of the lattice with all the area in between being wild green space) it’d be a better system. So, it’s because of the extreme size to where the airflow is pretty close to straight, after going through the funnels, can that be made to work? It may work best by using narrow airfoils. The objective is to also make the “blades” be of very light material: since there isn’t the need to withstand the huge g-forces or account for hail or the like, I’d like to think it could be made to work, but I do have a number of basic sanity checks to try first. At least this VAWT concept can have the basics tested cheaply, and it doesn’t require building a whole city ;)
Hawt vs. VAwt - from the computer industry, the idea of TCO (Total Cost of Ownership). Since with a VAWT, you place most of the mechanical (and all of the complex mechanicals) at the bottom, much reduced need to climb a 100m tower with it's concomitant risks. I think they're less likely to catch fire, too, saving engineer lives (no bailout systems on the power heads of HAWTs). As to blade-pitch control systems, there might be some ideas floating around in the sailing world, specifically wing-sail boats. I believe they are doing some good work in more passive control systems.
Fascinating vid! I live off-grid, and PV provides most of my battery-charge, generators supplying the short-fall as needed. This is not as un-economic as might seem, as I only use the gens when I have a higher-current device (washing machine, microwave oven etc) that needs powering. I have purchased and mounted an off-the-shelf HAWT (6m above ground), but due to wind-shear and turbulence, my mountaintop position falls far short of the output I was hoping for from my wind turbine. This despite strong winds during winter. Only very high-speed gusts (50-80km/h) produce enough rotational speed in the turbine to give me even 5-10 miserable amps into my batts, and then only for a few seconds. It's been an interesting and even valuable experiment, but will never pay off the investment in time and money. The same investment sown into fuel for my generators would keep them going for MANY hours of high output current right through many winters of low solar energy! I'd like to experiment with VAWT, but I need a solution weighted toward financial economy of installation rather than efficiency. Any suggestions please?
Thanks for commenting, it's really cool to hear real-world experiences like this. It's hard to say if a VAWT will be more successful for you. If the problem is that you have low wind speed where you want to put your turbine, then there is simply not much energy there for you to capture and a VAWT won't do any better. If the problem is that the wind direction is different than you expect due to an updraft or something, you could try to look into that (maybe attach some strings to your tower and see which way they blow) and adjust the orientation of your HAWT accordingly. But if the problem is turbulence (which you'd also be able to see with a string test) then a VAWT might work better. To get the economics right, you'll need one that is reliable so probably best to find a manufacturer with a track record and some independent reviews from customers who have used it in a similar application to what you want to do with it.
Valuable information. I have always wanted to believe that vertical and helical turbine would be the most efficient. Clearly there is much more to the physics and implication for blade design than I thought. I would appreciate more discussion of the pitfalls of vertical design. We have solar panels and regular winds and have imagined a supplemental wind contribution. I really do not understand the losses to friction and component stressors in horizontal and vertical systems and would love a discussion and comparison of these isssues.
I would like to have seen more time spent on that. Helicopters change the angle of attack of their blades throughout each rotation to compensate for forward air speed, should be much easier with vertical axis wind mills.
Nice! You're the real deal obviously. Tricky stuff, plain language, clear take home messages that even I get. Would love a more mathematical vid though it'd be mostly lost on me. Keep doing your thing.
Hi Rosie. Our presentation is simply fantastic. Congratulations for presenting us with such an interesting and complex topic in a way that is so much easier to understand. Surely, this reflects all your professional competence. Thank you very much, and may God bless you. RVC - Brazil
Are there any studies discussing the advantages of VAWT designs being easier on wildlife? Big vertical/curved blades would be easier to see and avoid, versus a HAWT with blades coming up or down at over 100mph that a bird won’t see? Thoughts?
Well done, Rosie. Thanks for the explanations. Compromise is usually best functionally. My 1st reaction is to place the complexity of function into the manufacturing process: for instance a helical design. Once the vawt is in place, if well-manufactured, the product should perform with little need for on-site adjustments and maintenance. This may be less optimal in energy generation than adjustable vanes/airfoils but better for long-term low maintenance.
Can we apply this to a blackbird type of vehicle preferably to a catamaran? I imagine there are forces on the pole that supports the blades that can be harvested for movement.
The possible approaches for VWAT simulation:
1. Cascade model+Leishman-Beddoes dynamic stall model.
2. Double Multiple Stream Tube model.
3. 2D Point vortex +Leishman-Beddoes dynamic stall model+free wake model.
4. Lift line model + +Leishman-Beddoes dynamic stall model+free wake model or vortex in cell method to deal with the complexity of wake.
5. Unsteady free wake Vortex Lattice Method (VLM) or Panel method.
6. CFD methods based on sliding mesh or overset mesh technique and URANS.
Thanks for adding this information! It's complicated, isn't it?
@@EngineeringwithRosie Yeah. It needs a lot of effort.
Choice of method depends on solidity...for high solidity a relatively simple approach is the cascade model with stall and flow curvature accounted for. CFD - yes, if you have software and a fast comp. Lift line works well - a good example is QBlade.
How about adding a hollow funnel/cone-like structure located below the VAWT? I remember seeing a patent describing it about two decades ago.
The patent claims the cone structure would allow to re-focusing the wind/air-flow that coming from opening located on bottom part of the cone, the focused air-flow then used to turn the already spinning VAWT, further increasing its output.
@@rashidisw a university in England just did the math and find if you position the vawts right they are more efficient than the big wind turbines on a large scale. Vawts are the future and the only certified one is the hivawt. This technology has been surpressed by Facebook and the government
These videos are gold dust. This is what TH-cam should be like as a norm. Authoritative and clear and no fear of the use of maths. Thanks a lot.
sometimes math doesntwork in reallife
well said!
Can you make the video of the maths and theory of aerodynamic analysis of a VAWT
Thanks for your comment, if I get a lot of people asking or liking your comment then I will make one! So far there are two of you who want to see more maths 😁😁
Would love to see a video on the theory as well. Thanks!
Also have you seen the parachute idea of utilizing wind power? Something like skysails?
Yes would appreciate if give detail theories and math on this.
@@EngineeringwithRosie I just found this by accident. And probably by TH-cam algorithm secrets... 😉
I would be very, very interested in some more maths behind. I need the for-dummies-version, though. If that is at all possible.
Non the less, I think something like this should be on every roof. Even if it's just at 20-30% efficiency with a small battery backup.
This could help to keep the fridge running if the power is out for a slightly longer time.
And with more and more tech in every home, a small power backup would help save equipment and files by giving people time to shut down their computers, etc.
Compared to a horizontal wind turbine, a vertical design is probably much better suited to install on the roofs in an urban environment.
I think 60 likes is a lot :)
I live in north Texas with constant, powerful wind. I use VAWT exclusively, utilizing both Darrius as well as Savonius designs I have refined over the past 57 years. I am 74. My vawts have completely overcome flutter, stall, vibration, over-speeding problems as well as have zero electrical loading and unloading with wind speed and frequency changes, because one design utilizes 4 moving parts, while another utilizes 2 and ALL my birds compress air into an air grid for storage. Electricity is manufactured in my shop utilizing any of several air-driven engines of my own design. I have several air-driven appliances I have manufactured over the years.
Edit: New Sub. I love physics!
Sir, We live in a typhoon belt island, will be able to share your idea on how to build DIY a small 3 KW VAWT unit for my house?
Great video !!
I'm a retired mechanical engineer and I'm building my dream ranch totally off grid and as much recycled materials as posible.
I've built a vawt at my off grid home to suppliment the solar system. I've tried several airfoil shapes and materials most of which have failed.
I've studied that vawt are self governing and with our near constant wind here and gusts up to 80mph, that's a plus.
At the moment I've settled on 55 gallon drums cut in half as I hope to make this easy and inexpensive to replicate for the Free seminars I plan to give this year.
I live in the poorest county in the U.S. and want to give hope to those who have very little and build their self esteem and confidence.
We also have outrageous electric costs !!
I have a total of $30 invested and my smart drive washing machine alternator/ motor makes 27 volts and 10amps in a 15 mph breeze.
All of the design work I owe to the University of U-Tube and thanks for you and everyone sharing your skills to help the world.
Charlie
Awesome you are able to sustain yourself. That's all you need to do in on order to get out of the energy money pit we're going to fall for now.
@@RedBatteryHead
Hello and thanks for your reply.
I used to build nuke plants and high rise buildings in Chicago.
I sold my $400,000 dream house,( the greenest house in the state) and moved to northern AZ in 2014.
Now that my children are off on their own, I get to live out my dreams of minimalist, self sustainable living. I have community water and power on my lot line but will never tie into it. I refuse to become a consumer !!
I'm finishing up a pure hydrogen fuel cell as I received the grapheen last week.
I've had good results with HHO but couldn't produce enough to run my car 100% on it and so had to run gas also. The mileage went from 44 to 54 mpg but this new system won't be on demand on the vehicle.
I'll make pure hydrogen from my solar powered system and compress it into an old LP tank and use quick air couplers to put into the car and drive away by turning off the gas pump and using it as back up power when the hydrogen runs out.
I'll also use it for my back up generator in tandem with solar and windmill power.
I can't wait to get up every morning and get to work !!
I really appreciate the University of U-Tube as so many great people are sharing ideas. I learn something new every day.
@@charleshughbryan5603 better use PV and swap to a BEV. Makes the most use of your electrons.
@@RedBatteryHead
Thanks for the tip but I'm recycling all I can here and found 250 watt panels for $50 each. I'm trying to repurpose as much as possible as folks here are hanging on by their fingernails and I want them to be able to replicate all I have.
I was an electrician in the Marines but mechanical is more my strong suit.
I believe I can blunder my way through showing folks how to install a simple system.
I'm building a tracking system for mine as I've heard a gain of 30% is possible.
I'm a newbe - sent here by Dave Borlace of "Just Have A Think". Great content - thanks!!
me too...
@@global_nomad. , me three.
us, four & five...
Me to
Ditto.
I understood about 1 percent of this but was fascinated enough to stay to the end. Thank you for providing me with much needed rest time.
Surely the case for VAWTs should include their advantages at larger scale. This is the "elephants cannot jump" argument. As any structure is scaled up, stresses in that structure increase as the scale, so if you make something twice as big it has eight times the volume and eight times the mass, maybe eight times the cost, and gravitational bending stresses within the structure double. This is a problem for HAWTs, because this increase in stress applies to gravitational bending in the blade roots and this is a fatigue driver and hence a driver of cost of energy LCOE from HAWTs. VAWTS do not suffer this same cyclic fatigue stress and so were thought in the 1980s (when I did my PhD in VAWT aerodynamics) to be destined to replace HAWTs eventually when wind turbines reached large enough scale. (Aerodynamic stresses become less and less important with increased scale.) As it happens we are actually clever enough to make bigger things more expertly and so things including wind turbines do not increase in mass as the cube of linear dimension, but rather mass increases as scale to a power of about 2.2 to 2.6. Amusingly we might remember that body mass index (BMI) is calculated from mass/height^2, not height^3. The effect of this is that gravitational bending stresses do not increase as scale, but they still increase strongly. To combat these increases in stress we hear that more expensive materials (kevlar and carbon fibre) are increasingly used in modern turbines, perhaps to cope with this gravitational edgewise bending fatigue problem. Presumably there will come a time when it will be cost effective to switch to VAWTs?
Can you enlighten as to which is the most efficient blade design of VAWTs so far please?
@@jazldazl9193 @Colin Oram -- I would love to know your thoughts.
study the 4 mw EOLE darelus that cost around $40 million
I have been a designer/consultant/inventor for many years and just wanted to say thank you
The scientific answer is unequivocally yes... I spent over ten years as a wind generator turbine and Axial Flux Alternator Design Engineer for the American Energy Research Laboratory. I designed, fabricated and studied many VAWT designs in dynamic environments. VAWTs are uniquely interesting but cannot compete with HAWTs in power generation on physical dimension characteristics. My data indicated the the swept area of a VAWT must be in excess of 4X that of a HAWT to produce a similar output energy production. That was when compared to the most efficient designs available.
As an example: A VAWT will require a physical size of +360 sqft swept area (10' X 36') turbine to produce the production of a 10 foot diameter HAWT with 81 sqft of swept area. Both turbines will produce "realistically" approximately 500-1000 watts.
Advertisers of wind turbines routinely indicate 2X - 3X more production based upon non-standard values.
If you are interested... You can also "guess" the useful output of a generator by weight. Since most "motors" are fabricated using the same components and materials I use a simple rule of thumb. 26 pounds of generator = 742 watts.
Once again.... Advertisers claim much much more due to various methods of non-standard calculations.
How do I know this? 11 additional years employed as an Engineering Technician for a major motor manufacturing company testing many different motor and generator designs and producing valid data to design engineers producing more efficient products.
Where do you recommend I look to compare retail generators suitable for VAWT diy? Thanks!
@@theosky7162 I do not recommend any VAWT. They are too inefficient for the investment. I recommend a small HAWT to supplement your solar system as part of a hybrid system design. I have attempted many VAWT designs new and old in research for efficiency. None exceeded the three blade common HAWT design. As stated earlier, It takes 4X the swept area of a HAWT to match its output capacity.
Unless you are doing hobby research I would not bother. There are hundreds of examples of VAWT deployed designs shut down around the world...
Buy a HAWT...
I get the efficiency problem of VAWTs as you have well explained. My question is directed at Generator sources or design class suggestions, as I noted your prior experience as an Alternator Design Engineer. Perhaps I'm still at the 'hobby research' stage, but my intent is to build a multi-input grid-tie system that supplies power to my home, manufacturing shop, and neighbors. As you are surely aware, technology in all the related fields is changing fast now. Solar panels, Battery storage, Wind Turbines, Capacitors, Transformers, Inverters, Hyperbolic collectors, etc... it's a deep dive on all. At the moment I'm concentrating on rotational to electric conversion. Any product compilations for capacity / cost / sources that you know of would be greatly appreciated.
@@theosky7162 I understand...First, let me explain my current build and strategy. I live NW of Amarillo outside any code restrictions. I live 100% off-grid. I have little knowledge of grid-tie systems. I designed, fabricated and distributed a couple of small wind generator APMA's. The designs were sound and extremely reliable but the overseas markets set the retail prices far too low to meet a standard business model. The company was American Energy Research. I sold all the fabrication equipment to Hurricane Wind Power several years ago.
Now, the good part!
I have built a solar/wind off-grid system to support a 20 acre location on a mesa far enough from Amarillo to not feel the "city" effects. I am still building, or expanding my system. Currently I have 60+ solar panels deployed and another 60 to be installed. These are 24v panels from 225W to 400W. I have upgraded my charge controller/inverter system from PowerJack and MpptSolar to MppSolar models 6048 & 6548 inverters. My system was 24V and upgraded to 48V. I still use GC-2 & GC-8 FLA batteries over 40 of them. I recently purchased (5) 5.2Kw EG-4 server style LiFePo battery packs for storage. Currently I only have one 400W 48V HAWT wind generator to "top-off" my battery storage system.
As I mentioned earlier a "hybrid" system is needed in almost all applications. Let me know where your install will be and I can give you a rough idea of the "mix" required to design a working system.
Wind is not an issue here as well as sun.
I am willing to help you in your quest if I can
Isn’t HAWT not suitable for areas with high turbulent typhoon winds? For potential future 30MW VAWT plant, how many turbine motor generators (of largest commercially available size) would you need at that plant?
Fantastic subject!! Are you ready for more?? Okay, let’s go.
Of course I think that VAWT have so many benefits! Coming from Holland and specialized in energy gives near endless options if you live in Canada.
Worked with hydraulic windmills horizontally, was in projects to tweak blades. But over all noice and high maintenance on bearings was cause for windmills to be out of service and expensive to maintain. Combined with space (minimal space required for VAWT), noise and added consequences make me aim for vertical. Yes, I see this as best for our future worldwide but we have some development to go through! Welcome in the miracle world, you bring us the future!!
Great Video!!
I'm Currently in my final year at university and I'm working on developing the Double Multiple Stream Tube model (DMST) to analyse VAWT turbine performance. So, I'm voting for this for the next video!!! Would love to see your breakdown of it, seen as it's an extension of this video. Or even the single/multiple tube model.
Hey wow, big project. Good luck! You will know more about it than me if you've been researching for a while, I should be asking you for advice!
It takes me months to research and finish a new video, so likely you will be finished before I get to it, which means it wouldn't be much help to you unfortunately. I would be interested to see your project though, so please post a link when you're done (and tag me so I get notified).
give us the math!!!! i love your work. it is verry inspiring
Thank you! I will add your vote to the "yes to maths" column 😁
@@EngineeringwithRosie maybe even with Modelica, so we can use the math you did 😆
Yes to math over here too
Yes, I want all the references citations & books. As an Aerospace Engineer with access to CFD codes from my desktop computer, analyzing a number of different VAWT designs is easy. "Cry, Havoc! Let slip the dogs of design", Unfurl the knowledge to the winds, the unexpected will happen. JSW
YES ! Bring the MATH ! :P
Jokes aside, I would be interested too !
I am also interested in the detailed design video with all the math :-)
Floating VAWT have a good future as size can grow but with moving parts closer to ground level they are easier to maintain. For floating, the stability of the VAWT very important and does not require huge engineering and materials like HAWT structures!!
Great presentation! Nice to see someone not treating me like an idiot when explaining something. As I see it, the biggest ADVANTAGE of VAWT is having the "guts" at ground level. The biggest DISADVANTAGE of the Darius-style is that they're not self-starting - but that can be fixed by having a Savonius-style starter turbine.
My take on the VAWTs is that they tend not to chew up a lot of real estate, so, might be more practical for off-grid applications, especially if you need to run multiple turbines due to relatively low efficiencies. I am not an engineer, but I tend to see things from an engineer's point of view. I would like to see a multiple turbine setup using the helical blade design. Another thing that wasn't addressed is the lowest windspeed for practical generation. I envision a hybrid setup with solar as the primary, and wind as the night time/cloudy day backup. Sorry, I have rambled. You gave me a lot to think about, thank you
Hi Rosie! Thank you so much for sharing your well-articulated and super informative videos here on TH-cam. You are a truly inspiring educator. I am a senior wind turbine control systems engineer in the U.S. and have recently been designing the control system and algorithms for a ~100kW H-type VAWT. The turbine has three straight fixed blades, all aluminum. There is no blade pitch mechanism. The lead turbine engineer wants to regulate power in high wind (region 3) via stall regulation by truncating rotor speed past a certain wind speed, thus stalling the blades to prevent increasing torque with increasing wind speed. However, this strategy will generate turbulent flow and potentially damaging vibrations that will lead to early fatigue of the blades and arm connections, as you so eloquently explain in your videos. It is also dicey trying to stall regulate in this fashion because the generator and electronic power converter equipment is required to have sufficient overdesign to handle the surge torque needed to decelerate the rotor in gusty wind in order to keep the rotor in stall. Any slop in the RPM regulation can cause a runaway condition whereby the rotor overspeeds to the point aerodynamic torque exceeds the electrical torque capability of the system, thus the rotor suddenly becomes impossible to decelerate without emergency brakes. The reliance on generator torque to stall the rotor also makes for poor power quality due to electrical torque fluctuations and surges. I have been trying to encourage the design team to consider a future blade pitching approach to simultaneously reduce stall-induced vibrations while also making speed regulation safer and more robust. I'm also concerned with their choice to use aluminum blades, as they will fail sooner, making for a poor quality product and disappointed investors. What are your thoughts? Are you available for consulting? Our company is based in Northern California and our current design prototype is located in the Texas panhandle and is nearly finished. We are commencing initial tests next week.
Hi! Thanks for this comment it is great to hear from someone working on a real-life VAWT project! Your concerns all seem very much in line with the experience of previous VAWT trials. Have you seen this Sandia report? It could help you communicate your concerns to your colleagues. energy.sandia.gov/wp-content/gallery/uploads/SAND2012-0304.pdf
I am indeed available for consulting, you can get in touch through my company email rosemary (at) pardaloteconsulting.com
I would share your concerns. A better arrangement to regulate power in high winds is to set the blade angle for as much anti-rotational torque as you can without stalling the blades (and then zero torque), but if you have no ability to change the pitch you are left with the electrical torque that the generator can produce, and as you observe, if this fails, you will get a runaway. To my mind any turbine needs an emergency brake, so it would be better to plan on implementing them from the outset.
Ive recently moved to a windy off grid location and have been wondering about VAWTs to make use of that wind, it seemed so simple to build in that the wind direction doesn't matter but it turns out there's a lot more to it than just the wind direction and length of the blades! Thanks for breaking it down so succinctly!
I would love to see a video detailing the basic mechanical needs and physics of a pitch controlled H-style VAWT. It would be interesting to see how complex it really needs to be. Loved the video!
just search "cyclorotor"
please make a video about full analysis, and pitching control in VAWT, since only with pitching they can reach a huge efficiency !
Hi Rosie! Thank you so much for all of your amazing videos! I started working for a company which supplies composite foams and balsas to LM Wind. Through that I was able to learn about and nerd out over wind turbines and specifically the blades.
I'm currently in the Rocky Mountains, USA. I think that locally we could harvest a lot of ancient and modern ideas for green environmental control. For instance I have been really interested in Persian Qanats and ancient evaporative cooling techniques. I've been thinking about, for instance, having a qanat where each wind-catching tower has a VAWT atop it- the fluid dynamics of the qanat help cool interiors while the VAWTS atop a qanat tower might assist with pumping needs or maintenance of the qanat itself!
Climate change is sadly irreversible and I neither an engineer nor a prepper but I am really interested in learning how to harness energy in nature to help us all survive in the future. Thank you Rosie for your awesome videos and inspiring content!
I have, over the past 50+ years, overcome ALL of the design limitations of my VAWTs.
I use a flat, symmetrical-section vertical "H" design started with a small Savonius rotor at the center. My largest vawt swings a 10-foot arc.
I deal with efficiency down on the ground by tweaking how I use the constant energy supply provided by my several turbines.
ALL my turbines compress air, and I utilize that stored (in air receivers) potential energy against pistons or pelton-wheel turbines down on the ground, safely inside my shop.
I'm 74 years old, and ALL my VAWT towers are counter-balanced, so they fold down easily with just one hand. My tallest turbines are 20 feet tall.
I am working towards having 30 VAWTs all compressing air. I store at 120 psig and use automatic condensate drains and check valves on all receivers. I haven't had any mishaps yet and it's been going on 60 years since I started.
What kind of compressor can I use with a VAWT. Thanks
@user-kr3pc1us2t
Any piston or diaphragm compressor will work. Stay away from sliding vane, flooded screw and any other high-speed device.
@@WhatDadIsUpTo Thank you very much. I am busy building my prototype Savonius. It will be a power takeoff for a pump or compressor or generator. Regards. Hennie Stander
Great video. Shows there are a lot of pitfalls in VAWTm design. I think they have great potential in urban areas without necessarily beating or matching HAWT efficiency...and I'd like to see the maths too
Just now, I did some basic calculations and used it to increase the VAWT efficiency by a whopping 43%. Such a simple solution.
Excellent video. One extra detail for those interested: aircraft wings are also tapered and twisted, for two reasons:
1) To reduce wing tip vortices (drag).
2) To make the outer parts of the wing stall later than the inner parts, to allow control to be maintained to get out of the stall.
Great video, Rosie. One thing I’d be interested to see is your thoughts and calculations on the clustering of VAWTs which I have heard increase their efficiency (unlike HAWTs which are disturbed by nearby turbines).
It would be interesting to make a VAWT with the actuated vanes. Make them out of composite. Put a steel-geared hobby servo at the root of each one with a battery pack. I'll bet with a lithium ion cell or two, that servo could last a long time. Have four vanes in the H-configuration. The base has the generator and a shaft encoder. Maybe have a wind vane and anemometer wired up through the center of rotation to the top. Have the servos control the angle of attack as it spins around, changing for speed and wind direction. Could be fun for a remote camp or mobile off grid situation. Just set it up somewhere and it should start and steer itself. Another idea: figure out some kind of angle of attack "circle" and use some kind of machine learning algorithm that would vary the load and angle of attack profile to maximize power generation, and then have it memorize that "map" for different wind speeds.
I have studied vertical axis turbines and came to the exact same conclusion as you: variable pitch is the answer. The efficiency is so much better. But I needed also to acknowledge: nothing for small, home scale turbines because of the explosive costs.
Nicely done! One potential use for VAWTs, where there may be an improvement over utility-scale HAWTs, is for floating offshore wind. The lower center of gravity significantly reduces the size requirement for the floating platform, potentially reducing the cost of energy. Of course, fatigue is still an issue that must be addressed, and there are a few tricks up our sleeves that might help. The US DOE is funding a program (ATLANTIS) that it includes a VAWT design component.
Hi everybody, I am such a DIY guy and I've started to build more than one VAWT on my backyard. I live in a place with 6m/s medium wind speed / year. So I 've done the math very simplyfied. 1 complete turbine (with generator, charge controler, batteries, inverter, etc) with the cost of materials up to 1000 euros and a medium of 500wh production for only 12 hours/day and 3 years of lifetime will make me save around 3200 euros of energy cost this 3 years. Minus the total costs, it can save around 2000 euros for 3 years. If we combine 2 of them the savings will double, so I can save 4000 euros for 3 years. For only 3 years of lifetime It looks enough efficient for me! In this case I think the low efficiency doesn't matter to much. And don't forget the carbon footprint. Mabe I'm wrong, I'll build it anyway.
Halfway through the video I was saying to myself "control the blade angle like a helicopter!" I'm glad that was validated at the end haha.
There is more effort than in the case of main rotor control mechanism of a helicopter, because:
- the wind can come from every direction
- each blade must be controlled individually within the whole cycle of revolution.
The first idea i had is to use 2 rotor axes separated by half of the blade width from a single axis which can be turned into wind direction. The blades overspan the distance between the axes and are therefore always in the correct angle to the wind, no matter where they are within the cycle of revolution.
Maybe, Rosie can comment on this.
Kind of seems like they just need the fastest feedback mechanism and some sort of PID control. There are some DIY projects out there for instance that are used for balancing brushless motors and props, using sensors to tell you exactly where the motor/prop is unbalanced.
To me an actively assisted passive pitch guidance system should be feasible. Put a cam on the central shaft with control rods to the blades. Rotate the cam with wind direction ...
@@jph219 Oh that's very elegant, I like it.
@@jph219 Eaxctly what I came here to comment.
I did a rudimentary vertical axis turbine to pump water for a small village using three sails...like the triangular sails in larger fishing boats. The sails adjust when facing the wind directly as well as when it faces the negative force. It however does need a bit of play on the sail's horizontal beam.
That sounds really cool!
Have you seen the Powerpod?
Promising or puff?
Thank you for the informative video!
You talked about the drag on VAWT when the blades spin around and essentially move back into the wind but wouldn't the exact same principle apply to HAWT? HAWT's have aerodynamically designed blades to counter this but then couldn't the Horizontal type apply the same? Also from an aesthetic viewpoint (in urban areas) personally I feel VAWT turbines have the edge.
What do you think of Icewind turbines?
I've been trying to figure out if any vertical design would work in the weak air pressure of Mars,
+1
Thanks for the suggestion, I'll add Icewind to my list for future videos.
The power in wind depends on wind speed, V, and air density, rho: P=0.5*rho*V^3*A
NASA gives data on the Martian atmosphere here:
nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html
It seems wind speeds are a little lower on Mars than on Earth, but not so low you couldn't use an Earth-designed wind turbine there. A bigger problem is that air density is much lower, only 0.020 kg/m3 compared to 1.225 kg/m3 at sea level on Earth. So there is only one sixtieth of the power available in Martian wind compared to Earth wind (at the same speed).That means you would need a wind turbine sixty times as large to get the same power, and even then you would get less power out of it on Mars than you would on Earth due to the lower average wind speeds. I don't see any reason why you couldn't get a VAWT or HAWT to work on Mars, but it wouldn't be very effective compared to what we're used to on Earth.
@@EngineeringwithRosie Thanks for the reply and data! :)
I'm interested in Martian wind power, because every so often a big martian dust storm blows along and cuts off the light for solar. Possibly lasting for weeks.
Having a way to keep batteries topped up (using the power of the storm) could be a life saver..
Am I right in thinking that the reduced density/power of the Martian air would make more light-weight turbines viable?
Turbines too fragile to last here on earth, could perhaps be mounted on solar arrays to provide a secondary power source.
I was picturing something like the Icewind turbine, made from thin aluminium and/or carbon fibre. Apparently, the Icewind's claim to fame is it's ability to operate in light winds.
It's not the easiest thing to test at the moment as I'm between spacecraft just now.
But I think wind power is being overlooked as a backup power source for a Mars base because of the low air density...
Anyway, thanks for the info and all the data driven youtube vids...
Lower wind speed or lower air density does give so smaller forces, but also a corresponding lower power production. So unfortunately you wouldn't see any reduction in the weight of a Martian wind turbine compared to one on earth that produced the same power, except with respect to gravity loads (self weight). I guess your fatigue loads for a horizontal axis turbine at least would be lower, so perhaps you'd save some weight because of that but not a lot.
Well given the success of Ingenuity, and its flights
I'm going to consider wind turbine power on Mars as a definite maybe!
It seems to show more promise as we learn more, so I'm keeping it on my list of candidates
Hi Rosie,
Lately I have seen talks about placing funnels around the vawt. Would that, in you opinion, be a path to follow to increase the efficiency?
Anything that can increase the wind speed seen by the turbine in low wind conditions will help, but in high wind, it would be ideal if the funnels could be reversed so that their action helped protect the turbine.
Can you recommend a commercial DIY kit? I have wanted to play with one as a hobby for a long time.
I do think VAWT has its own niche and should not try to compete with HAWT in terms of efficiency. However, we do need to find a way to improve its efficiency as much as we can while still maintaining its advantage over HAWT (omnidirectionality, lower cut-in speed, simpler design, etc). As you have mention in the video, for a distributed, off grid, remote area, and site with lower average wind speed, VAWT is the better choice over HAWT.
Finally, i loved your channel and i am glad it popped up in my recommendation algorithm ! Cheers from southeast asia !
I looked into getting a residentially vertical axis windmill and was disappointed that there were so few providers and that I was told to not put it on the roof of my house due to vibrations. Now I understand why, thanks for that
I wish wind turbines were as easy to put on roofs as solar panels but unfortunately that's not how it works!
Also unlikely to generate significant power, with a tiny turbine.
Check out Flower Turbines (flowerturbines.com/). They are a startup in Rotterdam, and will soon be producing turbines in the US, as well. They've patented a few breakthroughs in VAWT technology for residential and urban use.
I have just discovered your channel, sent here by "Just have a Think". I loved your presentation on VAWTs, something I've been interested in for ages. My reason for building one is to supplement my solar for my self sufficient lifestyle, which will include charging my electric vehicle. Most of the time I was watching I was saying to you (pity you couldn't hear me through this one directional medium) "What about an active blade turbine, have you ever heard of one?", and then towards the end you mentioned them. I hadn't heard of them before, except for the one I've designed for myself. I don't have the time or capacity at the moment to build it, however, I hope to do it late this year and early 2022. My biggest concern is the maintenance and wear and tear of the blade angle control system. I believe each blade will be contributing positively for around 300 degrees of the rotation, and I intend to build a 5 bladed version first up. I have built a small cardboard mock up of the blade control mechanism, and as I intend to control the blades with a cam and follower system, I'm also concerned it may be noisy. There will be challenges! But really looking forward to starting that project. I will also be checking out more of your videos.
That sounds like an awesome project! I agree with your assessment of the biggest challenges your design will face, it is good that you know that from the start so you can test out that part of your design first. I will be really interested to see your progress if you feel like sharing on the Engineering with Rosie Facebook or Instagram. Or you can can tag me here too if you make a video.
@@EngineeringwithRosie I will be more than happy to do that, and thanks for your interest, Mike.
Maybe you have made this video already but, I would like to see a use case analysis for a vertical wind turbine. Like, say a single family home wanted to install one; how much would it cost and when would the return on investment be?
It would most likely break down before return on investment. And a family home would never get enough power to make any useful difference. Just get solar instead. There is a reason why VAWTs are not used, and the companies that 'reinvent' them go out of business, 100 years after Savonius invented them. You'd think 100 years would be enough for optimization.
@@tzenophile That would be part of the assessment. Mean time between failures or MTBF. It is another metric we can measure.
@@moatplay An honest company would give you that. And you'd see that the sum would be negative.
@@tzenophile is it enough for optimists?
@@jazldazl9193 100 years? Do you know the definition of insanity? "Doing the same thing over and over again and expecting a different result."
Great lecture! I wouldn't have thought I can understand the workings of these turbines in 12 minutes.
I'd love to hear your thoughts on so-called "solid state" wind turbines or if those are just far too new and unproven to have much data/theory on them.
i am exploring vawt as a solution to a specific challenge on my sailboat. Small, quiet, doesn't have to be efficient - just consistent.
I love that you add a math component to your video......
For some reason this got in my recommendations... I'm not really an engineer, more a designer. But I wish I had you as my teacher back in my college days!
Can we please get the in depth video on VAWT design? Great video but I was expecting much more detail
Hi Rosie, when designing a VAWT, can one increase rotational speed at the centre (the generator) by placing the two straight blades (in an H design) farther apart? I am referring to a small VAWT for a cottage. I'm hoping to see 200 - 300 watts of power.
- very informative video! I think the Voith Schneider propeller's active pitch control system would make a great system to be adapted for use on VAWTs with active pitch control. Both the direction and the amount of pitch are variable so it would allow efficient operation over a range of tip speed ratios. The system has been used for many years on tug boats and other work boats/ships.
I would like your reaction to the VAWT of US Patent #9,494,136. All blades are interconnected forming a stiff structure.
Interesting, thanks! I will look into these topics.
Очень интересно вас посмотреть спасибо ! Но вы не сказали про саму форму лопасти какой она должна быть ?
I did my fourth year engineering thesis on this back in 1975. I was limited by computing power.
IBM 1130 4K punch cad input
I found my copy of the thesis a few years ago and it sparked my interest again. I was simply looking at the torque curve vs the speed ratio. It will rotate to a point and then the torque goes negative so it won't increase in speed. If you add a motor assist to brig the speed ratio over 1 then the torque value continues to increase. That's as far as I got. I never had the computing power to model 3 blades ( or more ). Nor did I try to extract power. I've always wanted to know the limit Betz Law on vertical axis turbines. I've always assumed 3 blades to be the most effective simply because of the accumulation of the sin curves like three phase power but that's not valid. Are more narrow blades more effective than fewer wide blades? Is there an optimum diameter? I just used 3 airfoil designs.
@@easternwoods4378 Thanks for sharing this, it's fascinating to hear about
@@RobBCactive All I was able to do was rotate the "wing" in relation to the central axis and then transit around the central axis to find the toque curve. Once you get over a speed ratio of one the wing has a velocity approaching the leading edge. It's the same a foiling in the America's cup down wind.
@@easternwoods4378 I have trouble seeing why it generates torque when the wings are rotating through 360⁰, I would expect it all to cancel out.
@@RobBCactive What I did was rather rudimentary. At a low relative velocity the wing going upwind will have a relative velocity of v ( wind ) plus the rotational velocity. The wing going downwind is v ( wind ) minus the rotational velocity. In effect the wing has the trailing edge facing into the wind. In one rotation of the main axis the wing stalls several times. It effectively becomes just a barn door when the wing is perpendicular to the flow.
When you get to a speed ratio higher than one then even on the down wind side the wing is seeing the airflow coming to the leading edge. It does however oscillate between a positive lift and negative lift.
At low speed ratios it's basically an anemometer. At a speed ratio of one the torque is negative so it won't ever over speed on its own. Once you get to a speed ratio greater than one the torque output increases rapidly. the torque value vs speed ratio is an S curve.
The "trick" is to find the optimum wing angle between the radius from the center point to the wing and then angle the wing.
That's as far as I got. I never calculated the actual power output. It also means that you have to provide a power input to get to a speed ratio greater than one. It's hard to describe the the effect in words. I's a lot easier to draw a diagram.
are you using maglev to keep the rotator from contacting the stationary part of the vertical axis and creating drag? What about wing fences, either at the ends of the blades, or in the middle, to make the wind more laminar for a longer period of time??
The active blade pitch vertical wing could be achieved more simply on a flat wing with leading and/or trailing flaps / slats (similar to a jet's wing) rather than varying pitch on the whole wing. I think the wing could be made to fly at every point in its rotation by changing it from (relative) concave to convex.
I would like to see more on that.
@@jenshobroh1294 Someone else did it with mechanics, but I think the trend now is to use spiraled blades and more exotic shapes.
Hi Rosie, I have just discovered your Channel from a referral from "Just Have a Think". You are very knowledgable in the area of aerodynamics (among many other things) and I am wondering if you might have time to explain the way some yachts are able to sail faster than the wind - I'm thinking of those America's Cup yachts sailing in Auckland earlier in the year. How do they sail at 70km/hr when the wind is 15? And what happens to the aerodynamics when they go so fast?
If you are sailing with the wind (wind coming directly from behind you) there is no way you can sail as fast as the wind, the drag of the water is too great. When you are sailing perpendicular to the wind (the wind coming directly sideways to the boat) the canvas takes the shape of a wing, where the lift force of wing is directly forward. Sailboards have less drag on the water than deep hulled boats and can achieve speeds three times the speed of the wind when sailing perpendicular to the wind. Ice boats run on blades (very much like icescates) that reduce drag almost completely, so they are able to achieve speeds 7 times the speed of the wind when sailing perpendicular to the wind. The modern world cup sailboats use hydrfoils to lift the hull out of the water, thereby reducing the drag of the water on the hull. Once you view a sail as a canvas wing, you can fly across the lake and it feels magical. All aircraft and sailboats are based on a tradeoff between lift and drag. Air and water are both considered fluids; so I view wings, sails, and hydrfoils as the same entities. I hope that I was able to answer your question! I find sailing to be exhilarating and get completely separated from the rest of my life when I doing it.
@@bradneubauer4694 you can sail downwind faster than the wind actually! Not directly downwind in a normal sailboat, but perhaps you saw the Blackbird "land yacht" that was all over TH-cam recently? th-cam.com/video/CkhBskovitQ/w-d-xo.html
I covered that a bit in this video: th-cam.com/video/CkhBskovitQ/w-d-xo.html if you look in the description for that one, there are some links on other resources that answer the exact question you're asking.
Give us the math! Also, it would be great to talk about what makes an efficient generator, especially for slower speeds (e.g. low speed wind recovery with vertical axis turbines).
Is the nozzle effect used between buildings for vertical turbines? Redirect air to the with the wind turning rotators. Like in a watermill.
I was wondering the same thing. Isn’t that putting Bernoli’s principal to work? Perhaps use it vertically as in a rocket stove, taking advantage of the thermals created by asphalt in sunlight, for example. The exterior wind channel might also serve as a partial safety cover for the blades of the turbine.
The whole way through I was thinking about changing the blade pitch, except using mechanical means. Probably not as good as doing electronically (as you could then adjust for wind speed as well as direction), but there are some relatively simple mechanisms that could be used at least to increase efficiency, even if it isn't quite maximised.
Such as?
Dear Rosie
Will it be possible for those like me, not too technical, to get from you a blue print to built VAWT? I being looking all over and I was not able to find a trustful source to buid on, thanks.
Hi, I don't know of a resource like that but I will keep an eye out and share with you if I find something. Eventually I plan to make one myself and when I do I can make sure to document so I can supply plans. But that will take a long time (probably minimum a year).
I will wait for you when you ready, thanks a lot for sharing your expertise...
Mother earth magazine had a design way back in the day. You may be able to look that up???
Like many other viewers, I would love to see those math equations Rosie. Also it would be nice if you can tell us about any typical software that is used for those calculus. Thx!!
Man the content is so good! I love the editing, I love your smile and I really like your cursive speaking and cohesion and the confidence you output! First time here so thank you, madam!
I think they could be on top of power poles in areas that get a good amount of wind.
Thank you for the practical analysis. We are indeed considering the VAWT for urban Distributed generation and a rural environment where visual and noise aspects need to be minimal. I'll follow with interest any ideas that come up in that respect.
This was interesting. More math and CFD would be great. Thanks.
Hi Rosie, one of the problems with wind turbines is the destruction of birds and bats. Are VAWTs any safer than HAWTs for flying animals?
Yes. Because the rotating parts are always in the same areas. HAWTs turn so the blades change locations plus they swing thru the swept area at high speeds which is what gets the birds.
Great content! When talking about pitch variability in VAWTs, a helicopter swash plate comes to mind. The greatest loss in efficiency is likely scale, as the area comparison of presented cross wind between VAWT and HAWT just doesn't compare.
Vertogen are working on just such a design.
I watched this again in December 2021 and note that a paper was published this month which became available as a preprint about the time you published this presentation. It is based on thesis research by Joachim Hansen under the direction of Dr. Iakovos Tzanakis. What makes it interesting is the analysis of the collective effects of “farms” of VAWTs, with spacing and rotation direction as additional design elements. The citation is Renewable Energy, 2021, vol. 171, issue C, 1371-1381. It may be downloaded at no cost.
HI Rosie, greetings from Colombia. I wonder what is your opinion on ART wind turbines? Is ot worth the trouble? Thanks for your job in communicating this extraordinary world of wind power!
Hi Camilo, thanks for you comment. I don't know ART turbines, and I am just getting hits for paintings of wind turbines when I Google it! Can you share a link so I understand what you mean? Then I will add them to the list for a future video to look in depth at some VAWT designs.
@@EngineeringwithRosie commenting to hear his response, also instead of complexing the mechanics by rotating the blades to solve the negative force area couldn't u just use a one way filter membrane to allow force in the positive direction of the wind and pass-through of wind in the negative force area or u could go more complicated and use a full spherical gyroscope design like nasa uses to test astronauts in a zero spin scenario. Then in the negative area the blades would move up an down cutting the negative wind area space by half and creating a more stable center of gravity under the wind force. I wish I had the means to test both and both together but I don't so I'm just passing along my thoughts 🤔👍
I have a more gerneral question about windturbines. Why are there no ducted windturbines when they are more silent and efficent and why isnt there a impeller version of a ducted Turbine? Is this purly a structural problem?
There's a company called Halcium that is claiming to be developing a ducted WT. It's called Powerpod, but they have very little info out there backing it up. And tbh it has a lot of to-good-to-be-true feelings about it.
I think the biggest reason is that wind power depends on the amount of area swept by the blades, which is why industrial HAWTs are made as big as possible, they can sweep a larger area and so capture more power for a given amount of materials (and thus cost). Ducting increases efficiency, but adds material costs, plus limits the size.
Hi Rosie!
I love your channel and what you’re doing with it.
I accidentally put my comment as a reply to another comment, so it’s a bit buried now.
I am interested in wind turbines for off grid applications for small cabins. I will likely install solar systems and the wind turbines will be supplemental to the PV panels.
I have not done a formal wind study, but I looking into installing a weather monitoring station to start collecting data. I’ve live on the land for a year and that has shown me that we have gusty winds that are occasionally very strong. There is usually a slight breeze, but I would not classify the land as a high wind location.
Thanks so much!!
Tom
Thanks Tom, I found your buried comment already. And suggested that you measure wind speed so it seems you are way ahead of me there! Remember to take the wind speed where you want to put the turbine. Near to the ground it will vary a lot from one location to another even close by. Compare your data to published long term data to see how your long term values might look.
@@EngineeringwithRosie
Thanks Rosie! I’ll get a weather station and see what I discover. Since I wrote that comment, I’ve been paying more attention to the wind and realize that it’s much stronger and more frequent than I realized. Thanks for responding! 🙏🏻
I loved this piece and have pointed some of our customer at it. We make the Darrius helical turbine you refer to in the video. If ever you want to chat happy to talk.
Hi there! Please do make this more detailed video :-)
Good day Rosie, I do have a horizontal axis wind gen on my yacht. The blades regularly stall which causes vibration and then we also have the problem of the yacht rolling and pitching which causes centrifugal forces in all directions. So I was thinking of building a vertical vane. To control the different pitches as the blade is rotating I think a type of leaver system that runs on a cam could be made to control the different angles of attack. The cam can be mounted on the shaft with push rods and a cam follower on the rotating frame.
thanks for your efforts in wind energy, you are doing a good job, can you put more on Double Multiple Stream Tube with VAWT
I will try my best 😀 it's a big topic, so probably it won't come before the end of the year.
Another characteristic of VAWTs, that comes to the mind of a laymen, is that they have a smaller footprint. That is in terms of the volume of space around the turbine that needs to be clear of obstructions, in order to allow for the needed rotation. This means that VAWTs seem, to me, to be better suited to urban environments. By this I mean, antennas, guy wires, rooftop water towers, utilities like heating and AC, and so forth, become less of an issue to work around. And, while I was typing this, I thought about you having mentioned that VAWTs are better at dealing with turbulent wind conditions... which are highly prevalent around all of those large and variously shaped buildings.
I think the helical turbines look pretty good, almost like some art installation. If I wanted one I'd probably choose one of those.
Solid engineering mindset on this one.
Thank you for such a simple explanation of the aerodynamics for the VAWT.
I now have a better understanding of the efficiencies for this turbine.
Hello Rosie, very nice video. I now have a good understanding to what to design for while developing my own VAWT. Can you make a video on which type of airfoil (a lot of different designs available out there) is suitable for developing a 3/4 blade Helical-VAWT.
Thanks and Regards.
Here is an airfoil designed for VAWTs.
airfoiltools.com/airfoil/details?airfoil=du06-w-200-dt
It is very important to scroll down to the Cl/Cl v Alpha graph. The angle of attack is the X axis and the Lift to Drag ratio is the Y axis. The colored lines represent the Reynold number the airfoil is operating at, effected by the speed and the chord (width) of the airfoil.
There is a Reynolds number calculator in the top left corner in the Applications section. Based on the graph, a 1.5 meter wide airfoil operating at 10 meters/second would work very well. A 100 mm wide airfoil operating at 5 m/s would be worse than terrible. The characteristic of airfoils to perform poorly at low Reynolds numbers is why small, lift type, VAWTs are not popular.
Great question, great answer! I will include information on airfoils when I make a video on detail design.
Please tell what do you think about that types of VAWT:
1) "Round brackets" Darrieus 3-blades rotors
2) Darrieus 3+3 blades rotors with 3 stiffening rings or with one ring + stretch marks
(they wrote that such windmills can self-start even in a weak wind without spinning them up with a small Savonius rotor, due to the angle of attack of the blades of 3-4 degrees)
3) One of the most popular for DIY: Ugrinsky-type "paired wings", some of them is simple Novikov's rotor.
4) Lenz2: another most popular for DIY
Great questions, thanks! it's so helpful for me to know which specific designs people are interested in. Can you share a link to sketches of these types, I have not heard most of those terms before.
@@EngineeringwithRosie I don't know why, but TH-cam hides all my comments with links
facebook.com/groups/windturbinemakers/permalink/4004016506321339/
@@EngineeringwithRosie Please visit "DIY Wind Turbine Makers" group on the Facebook, and see Daniel Connell's models.
TH-cam hides all my comments with links
3) Ugrinsky-type rotor
th-cam.com/video/hrgYnmhwGtU/w-d-xo.html
"Just Have A Think" talked about putting VAWT's in the center margins of busy highways to capture the "waste energy" from passing cars. That would seem to fit the definition of a turbulent flow (opposing flow?) and might help with overall efficiency. The space is usually unused, and any power generated could be used to power roadway lights at night.
th-cam.com/video/gcSnwW5v3f8/w-d-xo.html
Hi Rose. I am very excited finding your channel. I also tried to design a VAWT ( Savonius ) with the intention to try and solve the
inherent problems like it extract less power , low rotational speed , big stress impulses on the structure , torque variances
causing impulses on the drive and generator , torque variances can cause difficult self start , upstream blade exerts a braking force
that is lost wind power in the swept area , upstream blade has low pressure at the back of the blade causing drag . Not really good
for electricity generation ( According to researchers) . I agree completely with you , you have to add complexity to solve problems. I would like to discuss my design with you . I believe it will solve 90% of all the problems the researchers tell us about. I did build a model for proof of concept .But I need somebody to help me with calculations but confidential because I believe it can be patented . Unfortunately I do not have
a big budget , it is a home project .I will appreciate it if you can help. I am Hendrik Stander from Pretoria in South Africa .Regards
We operate a maintenance hangar at a small danish airfield and I am looking into cleaning up our energy sources. Vertical axis wind turbines play a key role (beside our roof suitable for solar panels). The advantages are the possibility to utilise the air flow between two hangars without restricting the use of the area between these hangars too much. Horizontal axis wind turbines are more efficient, but require higher installation which is a problem on airfields. So there are application possibilities despite the lower efficiency.
I'm an MBA, so please forgive any obvious oversights....but what about a Savonius(ish) with partial shrouding? Imagine a shroud looking downwards that would be open 12 to 3 o'clock and 6 to 9 o'clock and shrouded 3 to 6 and 9 to 12 o'clock with a weathervane at 6. The 'intakes' could even be flared to increase the catchment and venturi effect. A simpler alternative would just be a quarter/half shroud at 6-9 to 12 on the advancing scoops. Vertical stacking of smaller HAWTs like a stack of pole mounted V22 Ospreys might be another way to limit lateral dimensions while harvesting more on the vertical. Just spitballing here...lol Love the channel...subbed. Thanks for the teaching.
That's not a silly suggestion at all, there are several designs that use that principle. If I do a follow up video on this topic then I will include some examples of this. Thanks for the comment!
@@EngineeringwithRosie You bet. Looking forward to anything you care to share. I've always been fascinated by all the potential energy around us. Especially in the form of talent. Peace to you, Rosie.
Very interesting Rosie! Umm, so what is a good simple design for a diy VAWT? 4 straight blades with the correct wing shape? 2 blades? 3? I suppose you would want to make the vertical arms holding the blades very strong, maybe add vibration reducing ideas...
Agree Rosie, I think we are heading for blended energy solutions dependant on the local ecosystem. Nice one Rosie.
Interesting Video,
I have applied multi stream analysis to extremely large VAWT with and without pitch control.
The approach :
For simplicity I have omitted end of blade losses and assumed an average chord length for a constant Re value on an aerofoil at a specific location.
The airflow was split into 18 segments matching each 10-degree azimuth locations to calculate loads on the aerofoil at every 5 degrees. At every 10 degrees the aerofoil would be considered as subject to two adjacent airflows.
The average tangential force on an aerofoil while in a segment was considered as a quarter of ( Force at start + 2 x Force at mid + Force at end ).
To get the power from each segment these average forces were multiplied by the number of blades and tip speed divided by the 36 overall segments.
For each segment a Cp is applied to the upstream wind to establish a wind velocity at the aerofoil for an accurate apparent wind velocity and a downstream wind velocity to be used as the upstream velocity on the leeward side.
The CL and Cd Values ( taken from Qblade ) dependent on the AOA and Re values are inserted to obtain a true tangential load.
The power ( load calculations ) from the segment is compared to the energy extracted from the wind and if the difference is significant: the Cp that was applied is altered.
If the Cp had to exceed 59% for the difference in a segment to become insignificant then there are 3 options:
Reduce the average chord of the aerofoil.
Reduce the number of aerofoils.
Reduce the Angle of Attack.
The total power output was the sum of all power extracted from the wind in the 36 segments.
( a very small amount bigger than the calculated power from each segment due to +ve differences )
With Controlled AOA of 16 degrees on windward side and 12 degrees on leeward side
The AOA was 0 between 355 to 5 degrees and 175 to 185 degrees
I noted that I had to reduce the AOA on the leeward side to bring the CP down to 59% in several segments.
The method of pitch control is based on aerodynamic balance eliminating the need for any servos.
The pitch constantly changes to maintain the specified AOA for the windward and leeward sides.
To minimise end of blade losses ( which I had ignore ) :
Are there any equations that take winglets into account?
Has Splitting the end of a foil into 2 close parallel sections to create a central parallel flow been considered?
It is interesting to note that the AOA could be increased in the 180-to-270-degree quadrant slightly but
the simplified cam-controlled and aerodynamic balancing system for the AOA increases the power by slightly more than 11 % compared to fixed aerofoils.
The non pitching result was very similar to that indicated by the power using Qblade.
Happy to share the spread sheet with those interested. Leave a request in the comments on maxwindpower.com
Hi
Thank you for the video.
I have two naive questions. The first question is whether you have rethought vawt for turbine farms given the recently published article on how (if I understand it correctly) hawt farms cause turbulence which lowers the overall efficiency?
The second question is why not place blades perpendicular to the circumference of the turbine? Then they will be a little like a sailboat. (For simplicity sake I am assuming four blades with 90 degree separation), when the wind is coming from behind the vawt beyond 6:00, the first blade at 6:00 (the closest) will get lift in the direction that part of the circumference is moving, the second blade at 3:00 will be pushed like a sailboat with the wind, the third blade at 12:00 will get lift in the direction that part of the circumference is moving, and the last blade will either be total drag, or its angle will be adjusted so it cuts through the wind rather than acting as a drag?
Thanks
Phil Troy
The first question: no need to rethink. That research has been somewhat misrepresented in mainstream media reporting. Wind energy engineers already knew there is decreased wind speed and increased turbulence downstream of a wind turbine.
Your second question I don't really understand sorry!
Very nice video !
Usually so many people say anything about wind turbines, especially for VAWT !
To my point of view, the best compromise for a VAWT is a Darieus twisted mode (twisted for a more constant torque as you mentionned).
I worked ten years ago of such project. It was so exiting to play with aera (and CFD), structure (FEM) and electrotech to control the speed (and the power).
May be you should notice this point for VAWT. Without furling and pitch for twisted, regulation can just be done by a controler on the TSR (to reduce efficiency)
Hi @Engineering with Rosie, I have an unusual request: how do you figure out the VAWT efficiencies of one where the vertical axis is a solid cylinder, instead of being hollow?
In particular, I’m thinking a very large diameter vertical axis compared to the size of the blades, with a rather large building in mind, and I do wonder if the diameter getting notably larger will result in gross inefficiencies for wind harvesting due to a lot of overlap. I’ve been working on a radical city concept that emphasizes system efficiency in economies of scale for size, and one of the observations I’ve made is when scale is done correctly, even if a smaller scale version wouldn’t be very efficient, if you can go huge, and integrate it as part of a larger overall ecosystem, energy usage can be greatly reduced, in a geometrically-related way.
Thanks!
Wow, that sounds interesting. I am having a bit of trouble understanding exactly what you mean. Can you link to a sketch or something?
@@EngineeringwithRosie I’m no graphics artist, I’m a computer geek by trade. So, perhaps you can visualize what’s needed with this description: for the VAWT, I’m looking at about a mile in diameter, and a similar manner of concentrating wind as used for a Tesla Turbine, with collector holes all the way around. The height would be perhaps about one story in height. The objective is to use the same principle as a Tesla Turbine, using the viscosity of the air to drag it along: the thickness of the “blades” would be optimized for the surface boundary effects in the same manner as a Tesla turbine. This sort of VAWT would be part of the top story of a large building that’s ideally not directly on the ground.
The big question to answer is if this can be made to work using the same principles as the Tesla turbine efficiently enough to be cost-effective. There’a no need for energy capture to be maximally-efficient, and a HAWT peaks out about 59% in theory. If something can work that’s more readily maintained, doesn’t create too much noise, and has a safe failure mode and what’s more, is part of a building already there (this city would be a lattice of giant 1 mile diameter octagons and intermeshing squares, about 500 feet wide for the edges of the lattice with all the area in between being wild green space) it’d be a better system.
So, it’s because of the extreme size to where the airflow is pretty close to straight, after going through the funnels, can that be made to work? It may work best by using narrow airfoils. The objective is to also make the “blades” be of very light material: since there isn’t the need to withstand the huge g-forces or account for hail or the like, I’d like to think it could be made to work, but I do have a number of basic sanity checks to try first. At least this VAWT concept can have the basics tested cheaply, and it doesn’t require building a whole city ;)
Hawt vs. VAwt - from the computer industry, the idea of TCO (Total Cost of Ownership). Since with a VAWT, you place most of the mechanical (and all of the complex mechanicals) at the bottom, much reduced need to climb a 100m tower with it's concomitant risks. I think they're less likely to catch fire, too, saving engineer lives (no bailout systems on the power heads of HAWTs). As to blade-pitch control systems, there might be some ideas floating around in the sailing world, specifically wing-sail boats. I believe they are doing some good work in more passive control systems.
Fascinating vid!
I live off-grid, and PV provides most of my battery-charge, generators supplying the short-fall as needed.
This is not as un-economic as might seem, as I only use the gens when I have a higher-current device (washing machine, microwave oven etc) that needs powering.
I have purchased and mounted an off-the-shelf HAWT (6m above ground), but due to wind-shear and turbulence, my mountaintop position falls far short of the output I was hoping for from my wind turbine. This despite strong winds during winter.
Only very high-speed gusts (50-80km/h) produce enough rotational speed in the turbine to give me even 5-10 miserable amps into my batts, and then only for a few seconds.
It's been an interesting and even valuable experiment, but will never pay off the investment in time and money.
The same investment sown into fuel for my generators would keep them going for MANY hours of high output current right through many winters of low solar energy!
I'd like to experiment with VAWT, but I need a solution weighted toward financial economy of installation rather than efficiency. Any suggestions please?
Thanks for commenting, it's really cool to hear real-world experiences like this.
It's hard to say if a VAWT will be more successful for you. If the problem is that you have low wind speed where you want to put your turbine, then there is simply not much energy there for you to capture and a VAWT won't do any better. If the problem is that the wind direction is different than you expect due to an updraft or something, you could try to look into that (maybe attach some strings to your tower and see which way they blow) and adjust the orientation of your HAWT accordingly. But if the problem is turbulence (which you'd also be able to see with a string test) then a VAWT might work better. To get the economics right, you'll need one that is reliable so probably best to find a manufacturer with a track record and some independent reviews from customers who have used it in a similar application to what you want to do with it.
Valuable information. I have always wanted to believe that vertical and helical turbine would be the most efficient. Clearly there is much more to the physics and implication for blade design than I thought. I would appreciate more discussion of the pitfalls of vertical design. We have solar panels and regular winds and have imagined a supplemental wind contribution. I really do not understand the losses to friction and component stressors in horizontal and vertical systems and would love a discussion and comparison of these isssues.
With a "yaw tail" (to adjust for wind direction) a variable angle of attack can be controlled with a cam.
I would like to have seen more time spent on that. Helicopters change the angle of attack of their blades throughout each rotation to compensate for forward air speed, should be much easier with vertical axis wind mills.
I swear you made this so much easier to understand
than my college professors. Thank you so much you are great
I was thinking on putting a VWAT on a sailboat instead of the horizontal one.. any thoughts on this application?
Nice! You're the real deal obviously. Tricky stuff, plain language, clear take home messages that even I get. Would love a more mathematical vid though it'd be mostly lost on me. Keep doing your thing.
Hi Rosie.
Our presentation is simply fantastic. Congratulations for presenting us with such an interesting and complex topic in a way that is so much easier to understand.
Surely, this reflects all your professional competence.
Thank you very much, and may God bless you.
RVC - Brazil
Are there any studies discussing the advantages of VAWT designs being easier on wildlife? Big vertical/curved blades would be easier to see and avoid, versus a HAWT with blades coming up or down at over 100mph that a bird won’t see?
Thoughts?
Well done, Rosie. Thanks for the explanations. Compromise is usually best functionally. My 1st reaction is to place the complexity of function into the manufacturing process: for instance a helical design. Once the vawt is in place, if well-manufactured, the product should perform with little need for on-site adjustments and maintenance. This may be less optimal in energy generation than adjustable vanes/airfoils but better for long-term low maintenance.
Can we apply this to a blackbird type of vehicle preferably to a catamaran? I imagine there are forces on the pole that supports the blades that can be harvested for movement.
Thank you Rosie for introducing VAT