CFD Convergence problem


#1

hi there
my name is jurica and i am using simscale in FSAE . curently i am working on simulation with full aero package. so i put in my cad model in i meshed him. the mesh i think is ok not a lot of illegal cels or anything and i procesed to simulation so used step by step tutorial session 2 ful car aerodynamic and ok i do the same as tutorial says but my convergence plot look like this https://www.simscale.com/workbench/?pid=1534163617994316182#tab_2-0.
i dont understend why is this happening so if somebody can help i would rly apriciate it


#2

Hi @fcvjetnodrusto!

You do not need to be over 20 million cells and run your simulation - you can use a coarser mesh with approx. 10 million and see how the convergence looks like. For your case can you try removing the moving wall boundary condition for the single faces you picked at the bottom and rerun it? You do not have many illegal cells so I doubt that this contributes to the high fluctuations in the convergence plots. @Get_Barried & @vgon_alves, any input form your side is much appreciated!

Best,

Jousef


#3

Hi @fcvjetnodrusto,

Jousef has correctly stated that your simulation may be too fine. However, looking at your latest run in " full run 4" and the second “run 4” convergence seems to be good, you just need to set the maximum run time to be longer so the simulation can complete.

Cheers.

Regards,
Barry


#4

ty @Get_Barried @jousefm i complited simulation with your advices thank you very much