Hello sir, thank you for uploading this. Its very informative because I was always confused in this topic. Please keep posting the vedio like this on CFD.
Thanks Rohan! Yes, i want to keep posting CFD videos, particularly on the confusing topics. I have struggled with them for a long time and want to share what i have found to help everyone out :)
Hi, great videos. I find your explanations exceptional. Just one question if I may. Is "yp" the wall normal distance for the first grid point, or is it half this distance? Best reards
Hello Dr. Aidan. Thanks for these great contents. I completely understood how y+ is being calculated. I justed wanted to ask why we used the the log-law profile for calculating tau_w in Equation 6, andthen deriving Equation 7? In low-Re simulations, the first cell is not in the log-region. Is the explained procedure only works for high-Re simulations? Thanks in advance
Hi Aiden, thank you very much for these videos, I am very new to all of this and they are greatly helping. I'm a little confused by this one though, it sounds like Y* has all of the advantages that Y+ has but none of the negatives, so unless I am missing something here, why does Y+ still exist? It feels as if it should have been replaced by Y* entirely.
Yes, you are right. Y+ is historic and doesnt really have much use anymore as CFD codes use y* almost entirely. However, they are both available as quantities you can look at (try plotting them in your post processor and have a look). I would still recommend using y+ for your reports though, as many senior academics /professors / old cfd users arent aware of y* and might get a bit confused unless they are turbulence modellers ...
I would like to ask you, how to calculate the characteristic length of open channel flow?Y+ needs to be calculated when drawing the grid, so the value of the feature length needs to be known. I want to know whether the feature length of open channel flow is calculated by hydraulic radius or hydraulic diameter? Can you give specific formulas for reference?
Great explanation, along with the rest of your wall treatment videos, things are a lot more clear now, thanks! Is it not possible then to use nutUWallFunction for separated flows? In addition are the above equally applied in RANS and LES? Thank you!
Yep, you could use nutUwallFunction for separated flows. Just make sure your y+ < 5 (preferably < 1) if you want the right answer .... im not clear on the LES treatment yet, let me get back to you on that!
Hello, this is a wonderful video, but I have a quick question, regarding a point made at 10:10. How can y+ and y* (assuming you're in an equilibrium turbulent boundary layer) end up being the same, when tau_w, as a measure of shear stress, is a value that is independent of wherever your y is, whereas turbulent kinetic energy k_p is going to necessarily change depending on your distance from the wall?
Hi Minh, i will have to get back to you on this one. I think this is covered in the Launder and Spalding paper in their justification for using y* but i cant quite remember, since it has been a long time since i looked at it. In your CFD simulations, you can always just have a look at the solution for y+ and y* yourself and see that they are very similar.
Hello Aidan, I have a doubt regarding the implementation of the equation-10 in the slide where y_plus has to be computed iteratively. So the variable y_p in equation-10 refers to the distance of cell centre to the near wall (let's assume there is only one wall distance to account for simplicity). So for each cell, there has to be performed iterations to calculate y_plus of each cell, is that what I understood is correct? Can you please let me know? Secondly, for the implementation of say Van Driest damping function in a Smagorinsky SGS model, the formulation itself contains y_plus to calculate the parameter 'D' (which is used as nu_sgs limiter). So a commerical package like say FLUENT (which is y_star based) will compute y_plus or y_star?
Good afternoon, my y+ and y* are very different around the reattachment point of a separated flow (y+=5 and y*=21), is this to be expected as a result of the confused velocities at the wall? Or have I done something wrong? Thanks
Did you calculate y+ and y* yourself or did the CFD code calculate it? You may also need to be careful with the wall shear stress you are using in y+ formula. Recall that wall shear stress is a vector with 3 components and you need a scalar value to calculate y+. This could be the cause of your error ... Also, if you are a CFX user there is a 'solver y+' and 'y+' which give different values. Might be worth looking in the use manual to check what version you are using
@@fluidmechanics101 I got the values from Fluent post-processing so hopefully no human error there... I'm doing the classic backward facing step for some context, y* and y+ on the top wall are pretty similar but it seems they are not in agreement at all along the bottom wall. I guess my main question is should I be concerned/is this unexpected? Thanks
Hmmm if you are doing backwards facing step, you probably want to refine your mesh. Regardless of whether we look at y+ or y*, you should be aiming for around 1. The reattachment point is likely to be very sensitive to the wall normal and spanwise resolution so I would probably refine your mesh and try again? 2D backwards step is pretty quick to run so would probably be worth remeshing. I also doubt that y+ and y* will give good agreement around the reattachment point as the wall shear stress tends to zero at the inflexion point. Y* is probably more reliable
I am wondering, unless I am missing something in my reasoning, regarding the y* approach - when your first wall adjacent cell is IN the viscous sublayer, what is the physical meaning of kp there (as there shouldn't be any turbulence that near a wall) ? Thanks for the excellent videos, wonderful.
Correct. Physically there will be no turbulence near the wall as the fluctuations are damped by viscosity. However, the CFD code will compute a turbulent kinetic energy value in every cell in the mesh (even though the value is small). This small value is used to compute y* (which will also be small as we are in the viscous sub-layer). 😊
@@fluidmechanics101 yes, after watch ing your other video, it is my understanding u_tau is ised to compute kp, when the wall adjacent cell is in the viscous sublayer? Thanks. 🙏
Hi, I read from a reference that in viscous sublayer nu_t is in proportion to y+^3 and it is respected in low Re models like Launder-Sharma and Chien (while in Lam-Bremhost it is actually y+^4) ... Why there is a such difference?
I would probably go with k epsilon with wall functions (make sure your y+ is between 30 and 200). What is your flow scenario? Is it external aerodynamics or internal heat transfer, multiphase?
@@fluidmechanics101 I have one scenario where the flow is model over a hill for external flow, then a second one with internal heat transfer. Standard k-e with non-equilbrium wall functions was my thought for the external flow due to the curved surface. However I was unsure about the internal?
1. Calculate the wall shear stress. 2. Calculate the friction velocity (square root of the wall shear stress) 3. Plot a line normal to the wall 4. Extract the velocity along a line 5. U+ = U / friction velocity 6. Y+ = y * friction velocity / kinematic viscosity 👍
Excellent sir. If l have pipe or duct , the Re number based on diameter or Dh ,which correlation can I use to estimate the friction coefficient to get the shear stress
Fluid Mechanics 101 sorry sir I don’t understand what you mean . But if I have pipe or duct The turbulent flow will be exist when the Re number more than 2300 and the friction coefficient correlation differ For pipe to flat plate. I mean can I use the friction coefficient for the pipe instead of flat plate to determine it and then use it to determine the shear stress , the friction velocity near the wall and y plus
The simple explanation is: run your CFD calculation and plot y+ in your post processor. You want y+ to be less than 5 (1 if possible) over all the walls. If it isnt less than 5, go back to your mesh and make the cells smaller. This will reduce y+. Check again and keep repeating until y+ is less than 5. Y* is slightly different but you dont need to worry about it as they are basically the same 👍
Latex is the programme, with the beamer package for presentations 👍 it is free and works on all operating systems (Linux, Mac, windows) so you should be able to get it
Thanks for a great video. In calculating y+, what values of density and dynamic viscosity do we use? I believe we do not use free-stream values of the fluid for these; so does density and dynamic viscosity vary (just like y) as we calculate y+ ?
This depends on what type of flow you have. If your flow is incompressible and single phase Newtonian then density and dynamic viscosity are constant everywhere. If not, then take a best estimate for what you think density and dynamic viscosity should be near the wall. Remember that this is just an estimate for y+, you will have to go back and update the mesh anyway, so best to just go with your best guess here for density and dynamic viscosity
Hii Sir...Nice explanation..... Sir I have a doubt about plotting uplus vs yplus at any radial direction in Fluent. I seen uplus can be determined by u/ut....where ut can be determined from wall shear stress..What about yplus?Is it same as turbulent reynolds number defined in fluent? Can I make the plot b/w uplus and Ret.....which will be same as uplus vs yplus.... Pls help me on this....
Turbulence Reynolds number is not the same as yPlius. To make the plot normal to the wall you need to plot u vs y along a line normal to the wall, then plot wall shear stress vs y along the same line. You will notice that the wall shear stress is zero along the line except the first value. This is the value you should use to calculate utau, then uplus and then yplus for all the values along the line (you will need to do this yourself either in excel or matlab). I hope this helps
@@fluidmechanics101 Thanks sir...How to plot theta plus along the radial direction?In theta plus expression (Tw-Tp) term appears..how to take it?We need to fix Tw as wall node value and give local Tp values along radial nodes?
Yes, you are correct. This is a bit tricky to do manually so you might want to set up some scripts to do it. I usually use paraview as the python scripting is really good
Hello Dr. Aiden Excellent content and extremely helpful. I have one question what value should be used for density and dynamic viscosity for y plus. I am simulating a Heat exchanger and properties are defined piecewise linearly so I don't understand what value should I use for y plus calculations or put in reference values in fluent.
You will have to estimate! Maybe try something like the mean of the wall temperature and the free stream temperature. Then look up the properties from the polynomial. Remember, these are just estimates!
@@fluidmechanics101 Dr. Aiden thanks for feedback I will try different values. Sir I have few more questions, if you have some time can I ask them? Also keep continuing with the excellent work. I would recommend your channel to my peers as well.
Thanks.. 1) i am running simulations with 1.2 million cells but as i refine mesh to 1.8 million and 2.6 million cells results deviate further away from theoretical calculations instead of improving for heat exchanger simulations. I don't understand why? 2) I get accurate results for RNG at smaller mass flow rates but as I move towards higher mass flow rates results get worse and opposite happens for k epsilon realizable.
I think you need to be careful. Your results don't 'get worse' as you refine the mesh. The results get closer to a mesh independent solution, which may or may not match the experimental results. Once you have a 'mesh independent' solution, then you can start looking at reasons why your results may be different to the experiments. If you send me an email (FluidMechanics101@gmail.com) I can send you a copy of my 'CFD for professionals' course. It explains this idea in much more detail. I think it might be just what you are looking for!
Check your formula (1). If you use dimensions for the parameters on the right side you will get that Y+ has dimension of meters! So, it is not dimensionless!!!
5 ปีที่แล้ว +1
Fluid Mechanics Forces on Planar Surfaces Example th-cam.com/video/DY25-LD9wYY/w-d-xo.html
Aidan good video but this is not how things go in commercial software world. Though you did good with the video given the fact that this is most confusing area of cfd. I intend to write a book on wall treatment just for this reason. In commercial codes we do y+ then using this and k we try to find u-star or u-tau in your video. This u-star is the backbone of everything that your video missed (you did very good though). Then we compute y-star using yplus and u-star. Then in the end shear stress is calculated. Will be used for y plus and ustar next iteration. All softwares do things differently and there is no fixed one way. Even fluent has many approaches to get that ustar and shear after yplus.
Hi Parth, thank you for your insight. This is a confusing topic for users, as we often don't know what the code is doing and have to try and work things out by guessing! Your comments are really useful.Thank you
![[CFD] How Fine should my CFD mesh be?](http://i.ytimg.com/vi/60fDz2cVdy8/mqdefault.jpg)
![[CFD] How Fine should my CFD mesh be?](/img/tr.png)
![[CFD] What are Wall Functions and How do they work?](http://i.ytimg.com/vi/fJDYtEGMgzs/mqdefault.jpg)
Everyone saying thanks, meanwhile I just hit Y and missed enter xd
😂😂
Y and + haha
same hahahaha
@@ahyo8888 too XD
me too, but this is interesing
Finally, there is someone doing this kind of in-depth explanations of those parameters we use in the simulation. Well done!
Thanks Noah!
thanks a lot dear dr. aiden. it is impossible to find these materials as easy as here. I appreciate
i was searching for youtube but accidently typed y+, but nice video 👍
😂😂
Very explanatory video helping me a lot while getting through CFD literatures. Thanks a lot!
You upload exactly when I'm searching for it. Great explanation mate
Fantastic! Im trying to upload all the videos that seem to be missing from TH-cam
Once again. A brilliant and articulate lecture.
I really love your lectures, it is a great help in understanding CFD codes/models
Hello sir, thank you for uploading this. Its very informative because I was always confused in this topic. Please keep posting the vedio like this on CFD.
Thanks Rohan! Yes, i want to keep posting CFD videos, particularly on the confusing topics. I have struggled with them for a long time and want to share what i have found to help everyone out :)
I love your contents, many thanks from PoliMi ! 🇮🇹
Thank you for the explanation. Very helpful for me who is learning CFD.
Thank you man =) Great video! Precise and concise
Brilliant upload. Exactly what I was looking for!
man u rock, keep it up
Thanks for the video, very clear explanation indeed.
Excellent. Keep doing great job.
Thanks again for your support 😊
excellent video as always
Awesome explanation!
Hi, great videos. I find your explanations exceptional. Just one question if I may. Is "yp" the wall normal distance for the first grid point, or is it half this distance? Best reards
yP is the distance to the cell centroid. yH = 2yP is the height of the cell
Great Job, Thanks for sharing
Hello Dr. Aidan. Thanks for these great contents.
I completely understood how y+ is being calculated. I justed wanted to ask why we used the the log-law profile for calculating tau_w in Equation 6, andthen deriving Equation 7? In low-Re simulations, the first cell is not in the log-region. Is the explained procedure only works for high-Re simulations?
Thanks in advance
Hi Aiden, thank you very much for these videos, I am very new to all of this and they are greatly helping. I'm a little confused by this one though, it sounds like Y* has all of the advantages that Y+ has but none of the negatives, so unless I am missing something here, why does Y+ still exist? It feels as if it should have been replaced by Y* entirely.
Yes, you are right. Y+ is historic and doesnt really have much use anymore as CFD codes use y* almost entirely. However, they are both available as quantities you can look at (try plotting them in your post processor and have a look). I would still recommend using y+ for your reports though, as many senior academics /professors / old cfd users arent aware of y* and might get a bit confused unless they are turbulence modellers ...
Hello, thank you very mucha again. What an amazing explanation Dr Aidan.
Thanks again for the support Cesar :)
Great work . keep on please .
Excellent. you are a saviour
Fantastic, im so glad you found it useful 😊
Dr Aiden, can you please make a video explaining Two-Layer Model for Enhanced Wall Treatment..........
Super explanation.
Thanks Bro, excellent video!
Thank you so much,great job.
Thanks for sharing the information
I would like to ask you, how to calculate the characteristic length of open channel flow?Y+ needs to be calculated when drawing the grid, so the value of the feature length needs to be known. I want to know whether the feature length of open channel flow is calculated by hydraulic radius or hydraulic diameter? Can you give specific formulas for reference?
good job, dude. it helps alot
Great explanation, along with the rest of your wall treatment videos, things are a lot more clear now, thanks! Is it not possible then to use nutUWallFunction for separated flows? In addition are the above equally applied in RANS and LES? Thank you!
Yep, you could use nutUwallFunction for separated flows. Just make sure your y+ < 5 (preferably < 1) if you want the right answer .... im not clear on the LES treatment yet, let me get back to you on that!
For LES look for an implementation of the Werner&Wengle wall functions.
Well explained.
Hello, this is a wonderful video, but I have a quick question, regarding a point made at 10:10. How can y+ and y* (assuming you're in an equilibrium turbulent boundary layer) end up being the same, when tau_w, as a measure of shear stress, is a value that is independent of wherever your y is, whereas turbulent kinetic energy k_p is going to necessarily change depending on your distance from the wall?
Hi Minh, i will have to get back to you on this one. I think this is covered in the Launder and Spalding paper in their justification for using y* but i cant quite remember, since it has been a long time since i looked at it. In your CFD simulations, you can always just have a look at the solution for y+ and y* yourself and see that they are very similar.
Hello Aidan,
I have a doubt regarding the implementation of the equation-10 in the slide where y_plus has to be computed iteratively. So the variable y_p in equation-10 refers to the distance of cell centre to the near wall (let's assume there is only one wall distance to account for simplicity). So for each cell, there has to be performed iterations to calculate y_plus of each cell, is that what I understood is correct? Can you please let me know?
Secondly, for the implementation of say Van Driest damping function in a Smagorinsky SGS model, the formulation itself contains y_plus to calculate the parameter 'D' (which is used as nu_sgs limiter). So a commerical package like say FLUENT (which is y_star based) will compute y_plus or y_star?
Good afternoon, my y+ and y* are very different around the reattachment point of a separated flow (y+=5 and y*=21), is this to be expected as a result of the confused velocities at the wall? Or have I done something wrong? Thanks
Did you calculate y+ and y* yourself or did the CFD code calculate it? You may also need to be careful with the wall shear stress you are using in y+ formula. Recall that wall shear stress is a vector with 3 components and you need a scalar value to calculate y+. This could be the cause of your error ... Also, if you are a CFX user there is a 'solver y+' and 'y+' which give different values. Might be worth looking in the use manual to check what version you are using
@@fluidmechanics101 I got the values from Fluent post-processing so hopefully no human error there... I'm doing the classic backward facing step for some context, y* and y+ on the top wall are pretty similar but it seems they are not in agreement at all along the bottom wall. I guess my main question is should I be concerned/is this unexpected? Thanks
Hmmm if you are doing backwards facing step, you probably want to refine your mesh. Regardless of whether we look at y+ or y*, you should be aiming for around 1. The reattachment point is likely to be very sensitive to the wall normal and spanwise resolution so I would probably refine your mesh and try again? 2D backwards step is pretty quick to run so would probably be worth remeshing. I also doubt that y+ and y* will give good agreement around the reattachment point as the wall shear stress tends to zero at the inflexion point. Y* is probably more reliable
@@fluidmechanics101 Okay great thanks, will give that a go!
Thanks again for the help Aidan
I am wondering, unless I am missing something in my reasoning, regarding the y* approach - when your first wall adjacent cell is IN the viscous sublayer, what is the physical meaning of kp there (as there shouldn't be any turbulence that near a wall) ? Thanks for the excellent videos, wonderful.
Correct. Physically there will be no turbulence near the wall as the fluctuations are damped by viscosity. However, the CFD code will compute a turbulent kinetic energy value in every cell in the mesh (even though the value is small). This small value is used to compute y* (which will also be small as we are in the viscous sub-layer). 😊
@@fluidmechanics101 yes, after watch ing your other video, it is my understanding u_tau is ised to compute kp, when the wall adjacent cell is in the viscous sublayer? Thanks. 🙏
Hi, I read from a reference that in viscous sublayer nu_t is in proportion to y+^3 and it is respected in low Re models like Launder-Sharma and Chien (while in Lam-Bremhost it is actually y+^4) ... Why there is a such difference?
Not sure 😊 could you share the reference?
What turbulence model should be used if you do not have sufficient computational power to resolve the viscous sub-layer at wall boundaries?
I would probably go with k epsilon with wall functions (make sure your y+ is between 30 and 200). What is your flow scenario? Is it external aerodynamics or internal heat transfer, multiphase?
@@fluidmechanics101 I have one scenario where the flow is model over a hill for external flow, then a second one with internal heat transfer. Standard k-e with non-equilbrium wall functions was my thought for the external flow due to the curved surface. However I was unsure about the internal?
Yea k epsilon should also be fine for internal flow unless you have any seperated regions/diffusing sections. It is not the best for separated flow 👍
@@fluidmechanics101 Great, thanks for your input. Fantastic channel, keep up the good work! (Y)
Thank You.
Really good. Thanks a lot.......
sir, how can I plot u+ vs y+ for fully developed turbulent flow through a rectangular duct. please tell me the procedures.
1. Calculate the wall shear stress.
2. Calculate the friction velocity (square root of the wall shear stress)
3. Plot a line normal to the wall
4. Extract the velocity along a line
5. U+ = U / friction velocity
6. Y+ = y * friction velocity / kinematic viscosity
👍
Nice Video Bro , I like It
Excellent sir. If l have pipe or duct , the Re number based on diameter or Dh ,which correlation can I use to estimate the friction coefficient to get the shear stress
The flat plate correlation should be fine. Remember it is an estimate after all 😄
Fluid Mechanics 101 sorry sir I don’t understand what you mean . But if I have pipe or duct The turbulent flow will be exist when the Re number more than 2300 and the friction coefficient correlation differ For pipe to flat plate. I mean can I use the friction coefficient for the pipe instead of flat plate to determine it and then use it to determine the shear stress , the friction velocity near the wall and y plus
Please tell me more easily. about y+ I kinda didn't exactly understand
The simple explanation is: run your CFD calculation and plot y+ in your post processor. You want y+ to be less than 5 (1 if possible) over all the walls. If it isnt less than 5, go back to your mesh and make the cells smaller. This will reduce y+. Check again and keep repeating until y+ is less than 5. Y* is slightly different but you dont need to worry about it as they are basically the same 👍
Which program do you use to make the presentation? Most of my teachers used it, and i never knew which program they were using.
Latex is the programme, with the beamer package for presentations 👍 it is free and works on all operating systems (Linux, Mac, windows) so you should be able to get it
@@fluidmechanics101 tks a lot!
Thank you!
Many mannnnny Thanks!
Thank you sooo much :)
Thanks for a great video.
In calculating y+, what values of density and dynamic viscosity do we use?
I believe we do not use free-stream values of the fluid for these; so does density and dynamic viscosity vary (just like y) as we calculate y+ ?
This depends on what type of flow you have. If your flow is incompressible and single phase Newtonian then density and dynamic viscosity are constant everywhere. If not, then take a best estimate for what you think density and dynamic viscosity should be near the wall. Remember that this is just an estimate for y+, you will have to go back and update the mesh anyway, so best to just go with your best guess here for density and dynamic viscosity
I see, thanks Aiden. That makes sense. Keep up the great work!
Hii Sir...Nice explanation.....
Sir I have a doubt about plotting uplus vs yplus at any radial direction in Fluent. I seen uplus can be determined by u/ut....where ut can be determined from wall shear stress..What about yplus?Is it same as turbulent reynolds number defined in fluent? Can I make the plot b/w uplus and Ret.....which will be same as uplus vs yplus....
Pls help me on this....
Turbulence Reynolds number is not the same as yPlius. To make the plot normal to the wall you need to plot u vs y along a line normal to the wall, then plot wall shear stress vs y along the same line. You will notice that the wall shear stress is zero along the line except the first value. This is the value you should use to calculate utau, then uplus and then yplus for all the values along the line (you will need to do this yourself either in excel or matlab). I hope this helps
@@fluidmechanics101 Thanks sir...How to plot theta plus along the radial direction?In theta plus expression (Tw-Tp) term appears..how to take it?We need to fix Tw as wall node value and give local Tp values along radial nodes?
Yes, you are correct. This is a bit tricky to do manually so you might want to set up some scripts to do it. I usually use paraview as the python scripting is really good
Hello Dr. Aiden
Excellent content and extremely helpful. I have one question what value should be used for density and dynamic viscosity for y plus. I am simulating a Heat exchanger and properties are defined piecewise linearly so I don't understand what value should I use for y plus calculations or put in reference values in fluent.
You will have to estimate! Maybe try something like the mean of the wall temperature and the free stream temperature. Then look up the properties from the polynomial. Remember, these are just estimates!
@@fluidmechanics101 Dr. Aiden thanks for feedback I will try different values. Sir I have few more questions, if you have some time can I ask them?
Also keep continuing with the excellent work. I would recommend your channel to my peers as well.
Sure, ask away. It is always useful to put questions in the comments because other people can see the answers and benefit as well 😄
Thanks..
1) i am running simulations with 1.2 million cells but as i refine mesh to 1.8 million and 2.6 million cells results deviate further away from theoretical calculations instead of improving for heat exchanger simulations. I don't understand why?
2) I get accurate results for RNG at smaller mass flow rates but as I move towards higher mass flow rates results get worse and opposite happens for k epsilon realizable.
I think you need to be careful. Your results don't 'get worse' as you refine the mesh. The results get closer to a mesh independent solution, which may or may not match the experimental results. Once you have a 'mesh independent' solution, then you can start looking at reasons why your results may be different to the experiments. If you send me an email (FluidMechanics101@gmail.com) I can send you a copy of my 'CFD for professionals' course. It explains this idea in much more detail. I think it might be just what you are looking for!
Sir, what is C in the formula of y*? What is that quantity?
keep on !
I always end up here when I want to type "y" in my search bar to get to youtube but mistype and end up typing "y+"
😂
thanks men
where are you from?
Check your formula (1). If you use dimensions for the parameters on the right side you will get that Y+ has dimension of meters! So, it is not dimensionless!!!
Fluid Mechanics Forces on Planar Surfaces Example
th-cam.com/video/DY25-LD9wYY/w-d-xo.html
totally did not miss that enter button ._.
s a me
Aidan good video but this is not how things go in commercial software world.
Though you did good with the video given the fact that this is most confusing area of cfd. I intend to write a book on wall treatment just for this reason.
In commercial codes we do y+ then using this and k we try to find u-star or u-tau in your video.
This u-star is the backbone of everything that your video missed (you did very good though).
Then we compute y-star using yplus and u-star. Then in the end shear stress is calculated. Will be used for y plus and ustar next iteration.
All softwares do things differently and there is no fixed one way. Even fluent has many approaches to get that ustar and shear after yplus.
Hi Parth, thank you for your insight. This is a confusing topic for users, as we often don't know what the code is doing and have to try and work things out by guessing! Your comments are really useful.Thank you
@@fluidmechanics101 i wanted to reply but free speach platform youtube keep deleting my comment for no reasons.
That's a shame. You can always send me an email: fluidmechanics101@gmail.com
🔥🎆
I hit Y and + in URL XD
y+
ı THOught they were the same thing damn
Me too! An easy mistake to make 😄
me ecris y+ google
i yal ebna youtupe
xd