Ahmed body validation study help

Project Support
1

Hi,

I am trying to emulate the Ahmed body validation tutorial but I’m having some difficulty getting the correct drag coefficient. I have been trying to match the conditions of mesh 1 from the tutorial, but find I am getting a Cd of around 0.39 with a cell count of 4 million. I am wanting to get this value closer to the tutorial before increasing the cell count, but I do not know where I am going wrong. Here is a link to the project: https://www.simscale.com/workbench/?pid=4461036587810788701&mi=spec%3Ac68a2839-302c-4c90-8d10-106e800e29da%2Cservice%3ASIMULATION%2Cstrategy%3A3

Any help would be appreciated, thanks.

2

Hey there, and thanks for using the forum!

You write tutorial, but are you rather replicating this validation case?

I suggest you to check all the parameters in the reference project, specially the mesh refinements, so you have similar results.

Also, the numeric can play a role here, as I can see that your coefficients are not totally converged after 2000 iterations. Please also compare the relaxation factors.

3

Sorry, yes I did mean the validation case.

Thanks, for the feedback I will give it another go now!

1 Like
4

I have rechecked the parameters and refinements and I still get a higher drag coefficient of about 0.39. I also experimented with using a moving wall function for the floor instead but this did not help. Any ideas?