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Mass flow through cyclic boundary face

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Old   March 21, 2011, 05:31
Default Mass flow through cyclic boundary face
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JosÚ Rodrigues
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Hi

I am simulation a section of a combustor using cyclic BC. When I was calculating mass balance and energy balance I realized that the mass flow through the cyclic boundary faces does not cancel as it should (or shouldnt??).

Can somebody shed me some light on this issue?

THX

Jose
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Old   March 22, 2011, 09:38
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Karl-Johan Nogenmyr
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I have a faint memory of someone telling me this patch integration is not parallel (the cyclic patch crosses processor boundaries). If you have the possibility, you could try to do this on a single machine to find out if that works...

As said, a faint memory, but might be worth to check.

Regards,
Kalle
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Old   March 22, 2011, 12:00
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JosÚ Rodrigues
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Hi!

Thanks for your reply!

I solved the problem and here is how:

In the configuration I had before, I had set the cyclic patch manually in the constant/polyMesh/boundary, changing the patch type from wall to cyclic as follows (I first exported my mesh from gambit and then coupled the 2 faces with createPatch utility):

Cyclic
{
type cyclic;
nFaces 29022;
startFace 775347;
transform rotational;
rotationAxis ( 0 0 1 );
rotationCentre ( 0 -0.04 0 );
}

Then, if I eliminate the transformation entries ("transform", "rotationAxis" and "rotationCentre"), OF configures the patch automatically and now the mass balance is correct as it should be, SOLVING THE PROBLEM.

Anyway, I still dont understand what this parameters mean/do (I though I knew before ). I intend to look at the source for their meaning. However if somebody has a hint or answer ready to write here, it would be most appreciated.

Regards

JosÚ
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