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-   -   k-epsilon or k-omega or other models which is more appropriate for internal flow? (http://www.cfd-online.com/Forums/openfoam-pre-processing/117898-k-epsilon-k-omega-other-models-more-appropriate-internal-flow.html)

immortality May 17, 2013 00:57

k-epsilon or k-omega or other models which is more appropriate for internal flow?
 
in an internal flow with walls,inlet and outlet which model is more suitable for including both free stream outside of the boundary layer and also near the wall in the boundary layer so that can capture near wall phenomena the best?
Suggestions are appreciated.

jola May 17, 2013 02:49

Experts disagree. There is no clear concensus on this. We use SST k-omega for some applications, where secondary flows are strong and a model that is extra conservative for separation predictions is needed. For other applications we user a realizable k-epsilon model, which is easier to work with, converges better and is most often also conservative for separation (not always though)

immortality May 17, 2013 07:10

thank you Mr.Larsson
1)If i want to use realizable k-epsilon model how should i treat in the mesh?
I have regions of separation.should i fine the mesh til y+<1 or its sufficinet to be bigger and arround 30?
2)does realizable k-epsilon has an automatic function like kOmegaSST into itself that change to wall function near the wall when 30<y+<60?
Thank you so much.


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