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Sujatha November 4, 2013 14:09

Patches and walls
Hi all,

This could be a very preliminary question. But since am a newbie and confused I should ask.

What is the concept of patches exactly. How can i define a patch over a surface, like an obstacle in the dambreak problem.

I will be thankful to get any hint.

Thanks in advance

rendagar November 8, 2013 04:52

Patches and walls
I would also very much like some clarification. In the forum, documentation and software you come across the terms, wall, boundary, patch, baffle, face, faceSet, faceZone, cellSet, CellZone and perhaps even more however most are not really explained anywhere I could find. Perhaps one of the more experienced users would like to give an explanation of these terms.

At for your question of how to define a patch, I'm also new to OpenFoam so perhaps I'm wrong but I think you should look at the tutorial TJunctionFan in $FOAM_TUTORIALS/incompressible/pimpleFoam. Here topoSet is used to create a patch to apply a pressure difference. Applying a different boundary condition to the patch I think you would be able to introduce an obstacle in the dam break case.

TopoSet uses the file ./system/topoSetDict to specify the patches. By building up the patch one by one and exploring what happens using paraFoam (don't forget to check the "Include sets" and "Include Zones" boxes) you should be able to figure out how this works and if you can apply it to your case.

Hope this helps you along a bit,

Sujatha November 8, 2013 09:46

Thanks a million sir rendagar for your response. I will check the TJunctionFan tutorial and see.
I guess you might have seen the explanations for the wall and boundary given in the users guide and I too never had more information than that.

Once again thanks.

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