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How to create cyclic boundary(fan B.C.) in openFOAM200.

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Old   September 2, 2011, 18:18
Default How to create cyclic boundary(fan B.C.) in openFOAM200.
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Hello,
Are there any procedure I can try?
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Old   September 3, 2011, 06:14
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I would like to create cells like fig.b shown in the attachment. But, I get the cells like c.
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Old   September 4, 2011, 06:45
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How can I create cell shown in figure b, using snappyHexMesh and stl file?
regards,
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Old   September 5, 2011, 07:13
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Are there any ideas to merge faces red and blue shown as figure c? I want to get inner faces shown as figure b?
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Old   September 5, 2011, 14:33
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Greetings asamit,

AFAIK interior patches cannot be created inside a mesh in OpenFOAM. Mmm, I guess I'll quote (source):
Quote:
Originally Posted by http://www.openfoam.com/docs/user/mesh-conversion.php
Fluent allows the user to define a patch which is internal to the mesh, i.e. consists of the faces with cells on both sides. Such patches are not allowed in OpenFOAM and the converter will attempt to filter them out.
If you want to force the flow of a fluid, then you'll have to use something else, like setFields (see Breaking of a dam) or swak4foam.
You can select the cells that next to the desired STL surface and then use that cellSet as a reference in either setFields or swak4foam. I can't remember properly, but I think that setSet is what you'll need.

Another possibility would be to use one of the chtMultiRegion*Foam solvers, but this requires that you have two mesh volumes, not just one; i.e., you would have to split your mesh into two regions. See the tutorials at "tutorials/heatTransfer" for more ideas.

Best regards and good luck!
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Old   September 7, 2011, 08:48
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Hi, Bruno
Thank you for replying. I must examine swak4foam.
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Old   September 8, 2011, 07:35
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If I could use boolean operation between normalToFace and patchToFace, within setSet command, I could get the blue line shown in figure b.

Last edited by asamit; September 8, 2011 at 08:04.
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Old   September 9, 2011, 23:46
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This is wrong. constant/PolyMesh/faces already has red and blue faces, before applying patchToFace.
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Old   September 10, 2011, 10:53
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I modified constant/polyMesh/boundary by hand.
5
(
fan_half0
{
type cyclic;
→ nFaces 52;
→ startFace 25148;
matchTolerance 0.0001;
neighbourPatch fan_half1;
}
fan_half1
{
type cyclic;
→ nFaces 52;
→ startFace 25200;
matchTolerance 0.0001;
neighbourPatch fan_half0;

I would like to do this by command.
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Old   September 10, 2011, 21:57
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How can I reduce zigzag?
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Old   September 12, 2011, 03:01
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I give up on this. Next, I will try fieldSet and chtMultiRegion. Are they possible to simulate a P-Q? Any ideas?
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Old   September 20, 2011, 16:14
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Hi asamit,

I don't know if you figured out the solution to your problem, but here is a couple of old threads that I've reviewed just now: interFoam parallel - there you will have access to more information about a case that uses cyclic patches that are next to each other, which sounds a bit like what you are looking for.

As for modifying from the command line something in a dictionary/boundary file, look at the examples for using changeDictionary, by running this command:
Code:
find $WM_PROJECT_DIR -name changeDictionaryDict
Best regards and good luck!
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Old   September 23, 2011, 09:11
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Hi Bruno,

I gave up on checking chtMultiRegion or changeDictionary. I found fanPressure BC. It works fine. It does not require creating identical mesh that required for a Type cyclic.
Thank you for many advices.asamit
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Old   September 23, 2011, 09:51
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What about using baffles? (I have never used them myself). But from the tutirials, they seem to be designed to provide zero-thickness flat bodies inside the computational domain.

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Old   September 24, 2011, 20:42
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I have tried faceSet, cellSet, faceZoneSet, and createBaffles. But they did not work well with snappyHexMesh.

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