on volume elements and polyDualMesh

ramcdougal · February 21, 2012, 11:13

Let's say I have a tetrahedral mesh in Netgen. I export it in neutral format. At this point, I can check and see that it has both surface triangles and interior tetrahedrons. I can import the mesh into OpenFOAM via netgenNeutralToFoam. Are there still volume elements at this point?

When I view it in paraFoam with wireframe, it looks like it's just rendering the surface. I don't see any four-point objects in the geometry files, but I could be missing them.

I was hoping that polyDualMesh would give me 3d objects satisfying the orthogonality conditions I need for finite volumes. Does it? That looks like it's only working on the surface, but I can't tell for sure. (Slightly off topic: does anyone know something that does what I want?)

Thanks all.

Robert

elvis · February 22, 2012, 05:05

Hi,
search for older discussions on polydualmesh!
http://www.cfd-online.com/Forums/ope...tml#post180946

some discussion also point to problems for paraview/vtk

ramcdougal · February 22, 2012, 08:09

Thanks for the link, but you can be specific about what you're trying to suggest?

I can view the converted mesh just fine, but my question is: what am I look at? It seems like it's a mesh of the surface, not a mesh of the volume; is that correct? The posters in that thread seem to jump back and forth between thinking it's a mesh of the surface and thinking it's a mesh of the volume.

Later in the linked thread, they link to a slide presentation on fluent, which appears to be commercial software (no good; I need gpl-compatible), but their polyhedral cells are what I was hoping to get from polyDualMesh; do I have it?

February 21, 2012, 11:13	on volume elements and polyDualMesh	#1
ramcdougal New Member Robert McDougal Join Date: Feb 2012 Posts: 5 Rep Power: 14	Let's say I have a tetrahedral mesh in Netgen. I export it in neutral format. At this point, I can check and see that it has both surface triangles and interior tetrahedrons. I can import the mesh into OpenFOAM via netgenNeutralToFoam. Are there still volume elements at this point? When I view it in paraFoam with wireframe, it looks like it's just rendering the surface. I don't see any four-point objects in the geometry files, but I could be missing them. I was hoping that polyDualMesh would give me 3d objects satisfying the orthogonality conditions I need for finite volumes. Does it? That looks like it's only working on the surface, but I can't tell for sure. (Slightly off topic: does anyone know something that does what I want?) Thanks all. Robert

February 22, 2012, 05:05		#2
elvis Senior Member Elvis Join Date: Mar 2009 Location: Sindelfingen, Germany Posts: 620 Blog Entries: 6 Rep Power: 24	Hi, search for older discussions on polydualmesh! http://www.cfd-online.com/Forums/ope...tml#post180946 some discussion also point to problems for paraview/vtk

February 22, 2012, 08:09		#3
ramcdougal New Member Robert McDougal Join Date: Feb 2012 Posts: 5 Rep Power: 14	Thanks for the link, but you can be specific about what you're trying to suggest? I can view the converted mesh just fine, but my question is: what am I look at? It seems like it's a mesh of the surface, not a mesh of the volume; is that correct? The posters in that thread seem to jump back and forth between thinking it's a mesh of the surface and thinking it's a mesh of the volume. Later in the linked thread, they link to a slide presentation on fluent, which appears to be commercial software (no good; I need gpl-compatible), but their polyhedral cells are what I was hoping to get from polyDualMesh; do I have it?