SST komega convergence
Hi! I'm simulating a diffuser augmented wind turbine using a SST komega model. Residuals of continuity, turbulent kinetic energy and velocity decrease rapidly, but residuals of omega are stable (I mean really fixed on a constant value) on a higher value. Why? What can I do? I've got no problems with keps models (and the same mesh)

Re: SST komega convergence
Hello Mauri,
There are a few things that you can try to do. What works really depends on your situation (mesh, steady sate or transient simulation, boundary conditions, etc.)  try to do some iterations while solving the turbulence equation only.  lower the relaxation factor for omega, or, if it is really low, try increasing it.  adapt the mesh to the gradient of omega. Good luck! Wiebe. 
Re: SST komega convergence
Hello Mauri,
Ironically I had the same problem the past few days. I didn't want to look up turbulence levels for the input boundary condition, so I set it to zero until i would. It turns out that the SST komega model doesn't like 0 for both k and omega as inlet boundary condition. Hopes this helps for you too. Wiebe. 
Re: SST komega convergence
Hello Wiebe,
I tried to run some simulations and thanks to your advice things are better, in terms of convergence rate. And of course another problem has arised: when I refine mesh in order to use enhanced wall functions with y+<5 (using adapt menu in fluent, both in conformal mode and in hanging node), then I get a nonphysical solution, even starting iterations from a previous solution (which seems correct)! Sorry for still bothering you...and thanks a lot!!! 
All times are GMT 4. The time now is 16:06. 