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-   -   Patch Independent Method, Problematic Geometry (http://www.cfd-online.com/Forums/ansys-meshing/78204-patch-independent-method-problematic-geometry.html)

okan July 15, 2010 04:49

Patch Independent Method, Problematic Geometry
 
Hi,

I am new in cfd, and this forum. I am using Ansys Fluent 12.01

I have a centrifugal pump impeller's fluid zone, I want to mesh it with using "patch independent method". But the "Named Selections" cause "problematic geometry" and it is always occurs on "named selections". if the "named selections" are deleted, there are no errors observed. When I delete "Named selections" I cant create required boundarys. How can I handle it?

If "Patch Indepentdent method" is wrong selection, which method is better for me? :confused:

My Fluid Zone is like that:
http://img695.imageshack.us/img695/1206/39034610.png

Okan

PSYMN July 19, 2010 09:21

Refine the mesh to properly capture the Named Selection Boundaries
 
I remembered something about this, so I sent Ben Klinkhammer the link. He wrote back that...

Named selections force the PI mesh method to respect all the boundaries of the named selections. If there is not a named selection on a face, the PI mesh method will generally capture the faces, but could skip some of the edge boundaries. Putting a smaller size on the named selection faces will generally do the trick as then the mesher has an easier time capturing the boundaries. Reducing the sizes globally can also do the trick.

Unlike Patch Independent, Patch conforming mesh method meshes the edges first, then the faces, then the volume (PI meshes the volumes, then cuts out the faces, edges, etc.). So Patch conforming will generally not have the problem of capturing the edges, but you may get lower quality mesh as a result. (so you may still need to refine as necessary)

Generally when you run into this type of problem it is a result of a local mesh size being too large to get a good quality mesh that also captures the boundaries.

Hope this helps,
Ben

okan July 20, 2010 10:57

Thanks for your answer. I am followed the information you given me. It is working but the skewness is a little higher.

Thanks very much...

Okan


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