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-   -   Gas leaking along walls and boundary layers? (http://www.cfd-online.com/Forums/openfoam-solving/70048-gas-leaking-along-walls-boundary-layers.html)

kjetil November 12, 2009 19:15

Gas leaking along walls and boundary layers?
 
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Dear foamers,
I have a pipe case where water enters in one end, goes through a siphon, and exits through a diffuser at a lower z. Air enters through 6 small holes just above the diffuser, and I'm using compressibleInterFoam to solve this problem. But my problem, to be described, exists in the regular interFoam solver too.

It seams like the gas entering somehow manages to leak upwards, dispite the current flow of water of 4m/s. The air accumulates further up in the siphon and is not transported away, which is odd. The air enters at 2m/s through 3mm holes.

Are there any wall functions I should use, or is this problem related to the meshing (which I have described in another thread recently: http://www.cfd-online.com/Forums/ope...tml#post236057)

Also, the gas seem to move from the center of the pipe, and up. The air enters in the middle of the pipe - where it is almost possible to read "air1", "air2" up to "air6"...

Please see attached image of volume plot of alpha.


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