Limiters in k-w SST model?

Joachim · April 29, 2014, 16:01

Hey everyone,

I have one question regarding the k-w SST model of Menter. I am having some issues with my flat plate simulation.

1. I initialize the flow field with the free stream value.
2. I have a finite volume code, and I impose the value of w directly in the first interior cell (my ghost cells are given the same value, so that I have dw/dn = 0 at the wall).
3. The simulation diverges due to the very large change in w during the first step.

My question: Do people typically use limiters to prevent w from going from a small value to the wall value in one time step?
Also, is my approach correct for imposing the wall BC for w?
I have already checked my model with no wall (only decaying turbulence), and the results were fine.

Thank you very much!

Joachim

Joachim · April 30, 2014, 19:32

Actually, my simulation seems to work if I put limiters on my residuals.

Is there a rigorous way to do this? They typically use under-relaxation factors for pressure-based solvers. Is it ok to use the same thing for density-based solver? I guess that would be similar to using a very small time step...

April 29, 2014, 16:01	Limiters in k-w SST model?	#1
Joachim Senior Member Joachim Join Date: Mar 2012 Location: Paris, France Posts: 145 Rep Power: 15	Hey everyone, I have one question regarding the k-w SST model of Menter. I am having some issues with my flat plate simulation. 1. I initialize the flow field with the free stream value. 2. I have a finite volume code, and I impose the value of w directly in the first interior cell (my ghost cells are given the same value, so that I have dw/dn = 0 at the wall). 3. The simulation diverges due to the very large change in w during the first step. My question: Do people typically use limiters to prevent w from going from a small value to the wall value in one time step? Also, is my approach correct for imposing the wall BC for w? I have already checked my model with no wall (only decaying turbulence), and the results were fine. Thank you very much! Joachim

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April 30, 2014, 19:32		#2
Joachim Senior Member Joachim Join Date: Mar 2012 Location: Paris, France Posts: 145 Rep Power: 15	Actually, my simulation seems to work if I put limiters on my residuals. Is there a rigorous way to do this? They typically use under-relaxation factors for pressure-based solvers. Is it ok to use the same thing for density-based solver? I guess that would be similar to using a very small time step...