drag coeff to high - kOmegaSST turbulence model
 

Dear Users,

i have a problem with the drag coefficient calculated by the kOmegaSST turbulence model with the simpleFOAM solver :-(

The aim is to get to know about the drag coefficient of a streamlined body and compare this results with the ones got by the same body out of a wind tunnel experiment. So in fact - compare reality an CFD ;)

The coefficient i should get for cd is about 0.07, the one i got from my calculations is somewhat around 0.96...

I have calculated values for k and omega from the formulas out of the CFDWiki, but they seem to be incorrect - or a BC is the problem - i don't know :(

The eddy viscosity ratio i took was 1, but i don't know if this is correct for wind tunnel experiments...?

I will post my case files - maybe someone do have an idea...!?

Thank you very much in advance

Regards,

Martin

I got the solution...

After convergence of the first calculation with the uploaded case i got to high drag coefficients...
One need to change to higher order interpolation and gradient schemes...
i will post my updated fvSolution and fvSchemes here...

What was the calculated CD?

With the old fvS it was about 0.27 and now it is about 0.071

Nice work. How long did it take to run 5e10 iterations (5000/0.000001)?

Hi, I had a equivalent problem and what I find in my case is that : when I changed
- div(phi,U) Gauss Upwind -> Gauss linearUpwindV Gauss linear; I get 40 % of errror instead of 70%
and next I changed the turbulent quantities too :
- div(phi,k) Gauss linearUpwind Gauss linear;
- div(phi,omega) Gauss linearUpwind Gauss linear;

It's still running but after 100 iterations I get 10% less of error

Alex