European Hillclimb Hatchback Aerodynamic
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- เผยแพร่เมื่อ 5 ต.ค. 2024
- Using a common 1980's hatchback, this video will first of a series analysing the aerodynamics of cars seen on the European hillclimb scene. The model as a baseline is remarkably poor with a lift to drag ratio of positive one.
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I’d love to see this type of series for a traditional sedan body shape like a 3 series/Falcon/Evo
A better 90s v8 supercar front spoiler?
Or some kind of BMW sedan or Subaru Impreza which are very popular in sport competitions
Very interesting stuff. I have an old Starlet I compete with in the European hillclimbs and I struggle to understand some things around the hatchback aerodynamics. Obviously the car is much wider and lower than original Starlet and lately started looking into some aerodynamic aids like rear wing. Moved from the typical TRD style rear spoiler to a fairly big wing. I could see the benefits of the wing, increased downforce estimation from damperpots and by just feel is clear, but haven’t done any coast down or top speed tests to understand really the impact on drag. Also mounted it in a way that it won’t affect my pF as far back as the furthest part of body and as high as the regulations allow. I already thought about the extra airflow control on the hatch itself like the WRC style spoiler under wing you explained also on the other video, but haven’t had a chance to test it yet. What I have next in mind is to move the radiator in the middle of the car and feed the air from the sides of the car to the radiator and then out from the back of the car. Would be great to figure out the additional hatch spoiler and the cooling air out locations. I can either get the air in from the sides just before the rear fender flare or from the rear window area. Also my initial outlet point is the area between rear lights. This is typical in rallycross cars like this. Underbody I have nothing at the moment, but some sort of flat floor/rear diffusor would be possible at some point. This is what all the Golf’s and Polo’s usually have you show in the videos as examples.
The latest video got some legs on the algorithm and bunch have said they will try to work on something. It will be great to see if someone implements the window flap for next season.
Thats a nice car you got there!
This is a really good video and your channel has made CFD feel accessible to where I've installed OpenFOAM and given it a go. I've found the tutorials and videos on the topic to be very lacking though. I think a tutorial in your clear and easy to access format would do really well! Thanks!
theres many great tutorials for ANSYS Fluent CFD, obviously its not easy to get your hands on but a lot of the tutorials are likely applicable to OpenFOAM too. Worth having a look at
Awesome! makes me feel good you expanded research further than what we additionally tried! Really informative as always! maybe im going to add front vents...
That separation on the bonnet didn't go away.... or it only did when in a very specific window(when lower). I still may not be letting enough air through the front, but its a similar tactic that I used with the other model, suzuki
Interesting stuff Nelson, another cool video. Would be great to see some side by side comparison plots, or directly skipping throguh the still images to spot the difference a little more easily :)
Second vid of yours I've watched. Terrific content
omg loved it, so interesting to see how aero can help a boxy hatchback and now i know there's actual utility for the rear lips other than aesthetics.
Great video, Nelson!
Consider putting multiple variants of the same plot in 1 slide together, all it would need is like a few additional seconds, wouldn't make the video significantly longer, but would avoid us having to go back & forth on the video.
Are your models based on any of the OpenFOAM examples? Which solver are you using?
What tool do you use for mesh editing?
Finally, new episode of my favorite orn
Its really a great video, Could you make a video on how to do the post processing ? and mention the software's which you are using , Thank you
9% drag reduction? Even for a simple model that's relevant! Oh god need a spoiler for my 306
the reason every hatchback comes with one or at least a lip above the rear window.
Wohoo, new vid!
"Aerodynamics of Road Vehicles" by Thomas Schuetz gives the mk2 Golf CdA at 0.67 and lift coefficients in the order of 0.0x for both front and rear... A sim without cooling flow and simplified underbody should be reporting even slightly lower than that (I'm assuming no cooling?) . I'd be interested to see the mesh / geometry that was used to get the video results. The visualisation is done really well, but appears to show a solution that hasn't converged yet at 4:13?
This has much wider wheels and matching wheel arches. I ran earlier sims that gave values in the 380-60N range @30m/s. I can't remember the exact values, it was in the 300's, its in a spreadsheet on the CFD computer.
The other hatchback I simulated has a drag much lower. The Cd on the interweb was 0.43.. I think. 0.67 is really bad even for the 80's.
Its interesting that they are getting zero lift.... The wheel arches again are creating significant lift but not that much.
@@nelsonphillips The 0.67 is CdA, not just Cd. 350N at 30m/s gives CdA of 0.7 which sounds plausible for a non widened car. The lift prediction is quite tricky, but 1:1 lift sounds a bit weird. Small things on the geometry can throw it off a lot... how fine is the mesh and how "round" are the edges on the original model?
The mesh isn't the problem. If there is a problem it is with the model. Even so a hatchback with and without a spoiler will have lift at the rear. As you are quoting from a reference and assuming that it is correct then the car they have tested isn't a standard body, or base model or is even a different model. Air will inherently accelerate off the rear of the roof creating lift. This also entrains with the side flow creating a vortex, all creating lift. A spoiler as seen on all hatchback in the last 10-20 years disrupts this entrainment reducing lift and drag.
I have a feeling that the front gti air dam contributes in combination to the engine bay not being open enough. I'll have a look.
Can you do some aero of pikes peak cars?
First you insult VW. And the seventies racers.
And then it got too technical for me😂🤓😆👋👍