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-   -   continuity, k and epsilon divergence & skewness problem (http://www.cfd-online.com/Forums/fluent/109126-continuity-k-epsilon-divergence-skewness-problem.html)

victoryv November 9, 2012 17:58

continuity, k and epsilon divergence & skewness problem
 
Here is the problem,

I am trying to simulate (steady state) air flow in a room(with multiple rectangular blocks in it). The simulation is getting blown after certain iterations.Continuity , k and epsilon are diverging. I am using k- epsilon turbulence model. I have calculated the k and epsilon values and have given them in inlet boundary condition (0.005, 15). I tried to tweak the URFs but it was no use, the solution is still getting blown. Then I thought, may be it is due to the mesh. I checked the mesh quality and found out that the skewness factor to be greater than 0.98 (0.99998) and aspect ratio greater than 500. Then I tried to refine the mesh. But the problem was, even though after refinement there was no improvement in skewness. I have used patch conforming method with curvature option. I tried to use proximity and curvature option but the meshing is getting stuck.

Kindly suggest me something.

some general questions:

1.How to improve skewness and aspect ratio?
2.Is it fine to have aspect ratio greater than 100 ? ( I don't think so but I just want to conform it.)
3.I know one wont get proper solution if there is a bad mesh ( not deltax size but quality), but do the solution diverge if we have a bad mesh ( again not refinement but quality) ?
4.Is there any way to control the divergence apart from the URFs if it is not a problem in mesh?


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