It is a 2D simulation. The profile I used is NACA 0012. I used SST + transition (gamma theta) turbulence model. The residue cannot be converged under 1e-5. It just go periodically. Has anyone tried such kind of simulation before? Could you please give me some hints here?

http://www.cfd-online.com/Wiki/Ansys...gence_criteria

In this case it is almost certainly transient motion of the turbulence transition point and/or laminar separation bubble. You will probably need to do a transient simulation to get good convergence.

Glenn Horrocks

I am doing this for obtaining the lift and drag coefficients. When I do a transient simulation, these features oscilate much. How do you deal with it usually? Take an average? Cheers

Hi,

What do you do in the wind tunnel? Run it for a while and record the force against time and average it to get the final result. CFD is just a numerical experiment so do the same thing.

Glenn Horrocks