Cybertruck Aerodynamic Analysis | OpenFOAM 5

In this video I perform a comparative aerodynamic analysis between a Cybertruck, F150 and a brick. To make a long story short, the Cybertruck is significantly more aerodynamic than a traditional truck design, which surprisingly, is less aerodynamic than a brick!

Please enjoy!

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[MarcelNKemet]

I tried to reproduce the animation from the Github source code and couldnt't. The solvers complete but I can't get the volumetric rendering of the air velocity just like in the video. Do you have an additional paraview plugin setup?

[jay]

To not leave the "Limited mesh resolution" just hanging as is, grid independence analysis is often used. Essentially it's running the case with a coarser grid, and comparing the results. From that difference we estimate what would happen if the mesh was more refined than in our main case. If the differences are not that dramatic, the mesh is considered good enough. All in all - nice vid!

[tomhas]

Great video. I found the explainations just right in depth and speed. The result is kind of hilarious

[francescoberardinelli]

Nice video, which filter is applied on paraview for that cool postProcessing? Is it a clip by scalar or something like that?

[grideffect]

Thank you for the clear and honest explanation. Very informative, and I think you are a great communicator.

[miiortbiiort]

Awesome video and thanks for sharing the case files! Helped me solve an error :). I now finally have my first working LES simulation! :D

[adnanislam]

I find you videos helpful and inspiring. Subscribed 😇

[unchartedexe]

Did I hear that correctly? No inflation layers? My understanding is that aero sims without inflation layers are a total waste of time. You are missing the boundary layer effects.

[familyoddoye]

Wow this really shows the low comparitive drag of the cybertruck

[vito]

Hi, great video. I do have one question though, why do you multiply the z force by the pressure when calculating drag?

[chriskinney]

For the F150, I'd like to see the drag with a toneau cover over the bed and another without a tailgate. I'm assuming the tailgate is increasing the drag

[jeremyarnold]

So I have some thoughts. I'd be more interested in the aerodynamic coefficients than the total force. Why not use a symmetry plane to cut down on the number of nodes/elements? To really resolve the boundary layer and get accurate data you'll need a pretty fine mesh and multiple inflation layers on the models. I noticed your windspeed is around Mach 0.38. Compressibility becomes a factor at about Mach 0.3 so does your model actually have kinematic similarity to the full scale? Does the force and drag coefficient on the brick match what you should get for a real one?

[FaroukHaidar]

First of all, I appreciate your use of the Virdis color map :) One comment about the LES, it is strongly dependant on your mesh, such that the mesh be fine enough be to resolve 80% of your turbulent eddies/turbulent knetic energy. Therefore, at the back of the trucks, where probably a recirculation zone exists, you could increase mesh refinement by adding a refinement box in SHM to better calculate this region, this would effect could effect flow detachment and therefore your drag results. But doing this on a home computer is not easy, I understand, I suffer the same when running my some projects at home.

Also I think it would be very interesting to do a 2D analysis with RANS since the truck shapes are more or less consistent in you x-direction. The downside is that you cannot have nice animations of the flow with voriticies with LES (since it only works for 3D meshes). And I think usually you need a really low y+ (<1) near the walls to get reliable drag values that could be compared to experimental results, and that is also still dependant on what turbulence models to use. I have been using k-omega SST and want to also use LM transition SST model (4 equations so computationally expensive).

If you have wind tunnel data at a smaller scale, you could make your simulation models also smaller to lower the number of amount of cells needed. That is probably not the best and just equating the reynolds number would be more correct. Would be curious to see where you go from here :)

[markcoetzee]

I loves your video. I'm busy studying Numerical thermoflow and it's nice to see an example of how the theory I'm learning can be applied.
What pc species do you recommend for simulations like theses, because currently I have a 7 year i7 laptop and I was wondering if I should invest in a beefier laptop

[Crisis_Jones]

Put the analysis first and caveat it with the instructions are at the end please. Cool video.

[alexsfetcu]

Thank you for the tutorial :) When i run your cybetruck simple foam project i get following error: --> foam fatal error: invalid wall function specification. Patch type for patch topX must be wall. Current patch type is patch. Do you know the cause of this ? Thank you so much for the reply

[capnewport]

This is fantastic, for giggles can you run this at 100mph?

[punkisinthedetails]

What was the characteristic length for Re

[ken]

What about the smooth underbody of an electric vehicle vs the obviously not smooth underbody of the conventional vehicle?

[TheElipsus]

Hey very interesting video ! My only complain is about your rythm when talking, its a bit monotonous and lacked energy, otherwise presentation is clear !