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

Hello,
Are there any procedure I can try?

I would like to create cells like fig.b shown in the attachment. But, I get the cells like c.

How can I create cell shown in figure b, using snappyHexMesh and stl file?
regards,

Are there any ideas to merge faces red and blue shown as figure c? I want to get inner faces shown as figure b?

Greetings asamit,

AFAIK interior patches cannot be created inside a mesh in OpenFOAM. Mmm, I guess I'll quote (source):
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!
Bruno

Hi, Bruno
Thank you for replying. I must examine swak4foam.

If I could use boolean operation between normalToFace and patchToFace, within setSet command, I could get the blue line shown in figure b.

↑
This is wrong. constant/PolyMesh/faces already has red and blue faces, before applying patchToFace.

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.

How can I reduce zigzag?

I give up on this. Next, I will try fieldSet and chtMultiRegion. Are they possible to simulate a P-Q? Any ideas?

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: http://www.cfd-online.com/Forums/ope...-parallel.html - 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:Best regards and good luck!
Bruno

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

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.

Mirko

I have tried faceSet, cellSet, faceZoneSet, and createBaffles. But they did not work well with snappyHexMesh.

asamit