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-   -   Strange boundaries for k and epsilon (http://www.cfd-online.com/Forums/openfoam-solving/58200-strange-boundaries-k-epsilon.html)

henning December 16, 2008 09:42

Hi, I have a pipe looking l
 
Hi,

I have a pipe looking like this:

http://www.cfd-online.com/OpenFOAM_D...your_image.gif

and its extruded along the flow direction (z-axis).

When I run simpleFoam (3000 Steps) I get k and epsilon but unrealistic values. Also near the boundaries they look strange. k should go back to 0 and epsilon should rise constantly.

http://www.cfd-online.com/OpenFOAM_D...your_image.gif http://www.cfd-online.com/OpenFOAM_D...your_image.gif

I made a simpler case with a 2D channel and a similar mesh. Here the results look quite good.

http://www.cfd-online.com/OpenFOAM_D...your_image.gif http://www.cfd-online.com/OpenFOAM_D...your_image.gif

Any idea what i am doing wrong?

B.c.s for k and epsilon are zeroGradient (similar to the tutorial cases in simpleFoam / turbFoam) and just for the internal field I gave values. I also tried values on inlet but then I get an error message saying I need zeroGradient at inlet patch.

Thanks for your help

Henning


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