CFD convergence issue of a full body car simulation


#1

I have been working on a CFD simulation of an FSAE car but the residuals dont seem to converge in my simulation, The meshing and the Simulation parameters that ive taken are from this link in simscale

And since my CAD model is very close in dimensions to the project model i have been using it as a refernce.

Please can someone look into my project and tell me what do i need to change i.e Change the CAD, Mesh or the simulation parameters

Project link https://www.simscale.com/projects/siddhartha225/fsae-/

Thank you


#2

Hi @siddhartha225!

We will have a look at it and get back to you! Might be some numerical issue or boundary condition related as the mesh does not seem to have any problems.

Best,

Jousef


#3

Hi @siddhartha225!

I found a configuration that created a successful run but with way too high forces. I think (although the CAD is watertight) that the intersections still need to be fixed and the geometry needs to be cleaned up a bit further.

Attached some hints:

  1. \underline{\text{Fix intersecting faces}}

  1. \underline{\text{Another intersecting face}}

  1. \underline{\text{Sum up faces}}


In general splitting the surfaces is a must for the boundary layer to establish during the meshing process. Usually it might be better (also for efficient face picking) to sum up the small faces of the front wing lets say to a single “group” or faces called “front wing” for instance.

Tagging our experts @Get_Barried, @vgon_alves, @pfernandez as well as @yosukegb4 here.

Best,

Jousef


#4

Thanks a lot, i get on with cleaning up the geometry and trying to remove the intersecting face, I just wanted to ask what parameters did you change to get a successful run?


#5

Hi @siddhartha225!

I was changing the relaxation factors, a bit of the residual control and non-orthogonal correctors that are used for the pressure equation and repeat it which may reduce the influence of bad computational mesh but when the force is over 2E+101 even the correctors won’t help :wink: So it is good that you created some result control items to see if the results are in the right order of magnitude.

Best,

Jousef