SAS / RANS - Omega convergence

RodriguezFatz · September 17, 2013, 10:35

Hi all,

I run some pipe flow with bluff body case using the k-omega-sst SAS model (OpenFoam). I tryed many different numerical setups, but I can't get convergence for omega. (simulation was restarted, so all other residuals are already flat...)
picture_1.jpeg
Now, running the same numerics, boundary conditions, time steps,... with the regular RANS k-omega-sst model works:
picture_2.jpeg

Can anyone explain this? Or give me some ideas how to get convergence?

RodriguezFatz · September 23, 2013, 03:03

If you encounter the same problem: I found a possible bug. The report can be found here:
http://www.openfoam.org/mantisbt/view.php?id=1023

My omega boundary condition "omegaWallFunction" is accepted by openfoam (no error message), but it looks like the code doesn't use it at all.
Using a different b.c. for omega gives convergence, also for the SAS model.

September 17, 2013, 10:35	SAS / RANS - Omega convergence	#1
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 27	Hi all, I run some pipe flow with bluff body case using the k-omega-sst SAS model (OpenFoam). I tryed many different numerical setups, but I can't get convergence for omega. (simulation was restarted, so all other residuals are already flat...) picture_1.jpeg Now, running the same numerics, boundary conditions, time steps,... with the regular RANS k-omega-sst model works: picture_2.jpeg Can anyone explain this? Or give me some ideas how to get convergence? __________________ The skeleton ran out of shampoo in the shower. Last edited by RodriguezFatz; September 19, 2013 at 05:30.

September 23, 2013, 03:03		#2
RodriguezFatz Senior Member Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 27	If you encounter the same problem: I found a possible bug. The report can be found here: http://www.openfoam.org/mantisbt/view.php?id=1023 My omega boundary condition "omegaWallFunction" is accepted by openfoam (no error message), but it looks like the code doesn't use it at all. Using a different b.c. for omega gives convergence, also for the SAS model. __________________ The skeleton ran out of shampoo in the shower.

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