SimScale CAE Forum

Yaw Simulation for a fsae car


I’m trying to create a curved bounding box so as to simulate a car taking a turn. I tried making a bounding box on my cad software and then using it but the simulation failed, is there any option to make a bounding box similar to a toroid or torus?


Try using the extract fluid volume on a CAD file that has your curved bounding box on it and then do an internal simulation with it… But I do not think you will like the results you get by trying to ‘curve’ your flow…


Hi @markII!

That’s possible, meaning the simulation of “cornering” not the creation of a curved bounding box! Let me give you some resources for that:

Let us know if that helped!



I used that term loosely here… with internal fluid extractions, the outside wall is a ‘sortof’ bounding box that can be any shape you want :wink:


Same here, I should have mentioned that you can of course create an arbitrary shape for your bounding box but not on the platform, so you would have to choose a CAD software tool of your choice @markII! :wink:

Hope we could help you a bit!



But NOT if you plan to use HEX parametric meshing algorithm (SimScale, please allow internal meshing with HEX parametric meshes :pray: )


Well, I use HEX parametric for Internal CFD.

The project (I shared with you and Ric) is

Simulation: CylinderSlice_HEX+MRF




WOW, I stand corrected then, my memory is old on that one, thanks…


Maybe you can help with the mesh attempt at this Oct 2019 post where I try to do it?


WOW, great trick I just learned from you Retsam… I have to put a Background Mesh Box around/through my geometry and then select geometry faces for inlet,outlet,‘tunnel’ walls… :trophy:

Darn, I wish I would have thought of that :thinking:

EDIT: But wait, I did do that in my problem mesh above… @Retsam what went wrong :question:

Now I am a dog with a bone again here :wink:


I do not know what went wrong: For Internal CFD, I create my own BMB of any shape. It does contain a ‘negative’ of all geometries to simulate. So, If you assign the BC to that BMB, there is no problem. All internal geometry should be available for detailed BC definitions…


I guess Alex @afischer , couldn’t figure out why it would not work for my case too, since the topic was left unsolved … :sob:


Dale, what problem did you have in that case? I can reach out to the Fluid guys in our office so that one can reach out to you ASAP.

@Retsam, could you set the project to public? Cannot access it, thanks!




I will post a clarification of the problem in that topic, thanks… (Ooops, sorry if the non-powerusers do not have access to this issue, I created the Oct 2019 topic in the powerusers hidden forum category )


Yes, I did make it Public now…


Hi @DaleKramer,

I just really quickly checked your project. From the cell count and log you can see that your mesh simply resulted in a single hexagonal cell. I would need to check the sizing, but that’s a special point about the underlying meshing algorithm that it always creates a mesh even if the geometrical domain is captured in a totally invalid way for simulation. That doesn’t mean that you can not create internal meshes with the parametric mesher. We detect if the point is inside a body and in case there is a one to one map available also allow the simulation setup on the CAD.

Best Alex


You lost me there, is this trying to explain why Retsam can do it with his geometry and I can not do it with mine ?


No, my suspicion is that it didn’t work as I guess you are trying to create a quasi-2D mesh with only 1 cell over the thickness which resulted in a single cell for the whole mesh.

What to do if geometry does not appear in your mesh - try the Feature Trick

I will leave it to the coders and mathematicians to figure out why this Feature Trick made my ‘eye’ shaped BMB and geometry appear, but it did…