Geometry and meshing for OpenFOAM

Remy · August 6, 2009, 10:18

Hey everyone,

I am a new user of OpenFOAm and I want to use it to solve an internal flow in a rectangular duct with circular outlets. I don't really know what is the best way to set the geometry and create the mesh. Do I have to set all the vertices (and the inlet and outlet patches) in the blockMeshDict ? How is it possible to create circular patches then ?
I tried to draw the system with Blender and use the snappyHexMesh tool, but it seems that I still need to set the inlet and outlet patches in blockMeshDict. Anyone knows of a simple way to set up the geometry ?

Another question : what program do you use to open and edit stl files ?

johndeas · August 6, 2009, 10:21

I use Blender too, but I had problems with a triangular vortex generator that was meshed using snappyHexMesh, apparently without errors (no warnings in the last iterations), but still gave warnings when running checkMesh.

tomislav_maric · August 12, 2009, 07:02

Hello,

I'm using Salome-MECA and Engrid for meshing ships. I believe that Salome-MECA is really strait forward to use, especially for internal flows.

You just import the .stl file, create the geometry groups if you want (it speeds up the meshing process), mesh first the solid in 3D, then use submeshing to refine the original mesh.

You can download it from here:

http://www.caelinux.com/CMS/index.ph...d=46&Itemid=40

The installation is non-existant, you just execute ./runSalomeMeca in the local dir for a quick look and work, but later just source the lib and bin dirs and it runs perfectly.

SALOME doesn't edit .stl file, but there is absolutely no need. You explode the .stl into solid, face and edge components and build on that, adding perhaps additional geometry. You can have i.e. a railway car in the geometry module, but if you mesh just one plate, only that mesh gets exportet later. Conversion to FOAM is really easy. SALOME doesn't use metrics, so draw in meter dimensions, although scaling in OpenFOAM is really easy.

Yes, and when you add groups to the mesh, you assign the names. These names get exported as bcs in .unv file and through conversion to OpenFOAM mesh.

Hope this helps,

Tomislav

August 6, 2009, 10:18	Geometry and meshing for OpenFOAM	#1
Remy New Member Join Date: Jul 2009 Location: Den Haag, The Netherlands Posts: 5 Rep Power: 16	Hey everyone, I am a new user of OpenFOAm and I want to use it to solve an internal flow in a rectangular duct with circular outlets. I don't really know what is the best way to set the geometry and create the mesh. Do I have to set all the vertices (and the inlet and outlet patches) in the blockMeshDict ? How is it possible to create circular patches then ? I tried to draw the system with Blender and use the snappyHexMesh tool, but it seems that I still need to set the inlet and outlet patches in blockMeshDict. Anyone knows of a simple way to set up the geometry ? Another question : what program do you use to open and edit stl files ?

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August 6, 2009, 10:21		#2
johndeas Senior Member John Deas Join Date: Mar 2009 Posts: 160 Rep Power: 17	I use Blender too, but I had problems with a triangular vortex generator that was meshed using snappyHexMesh, apparently without errors (no warnings in the last iterations), but still gave warnings when running checkMesh.

August 12, 2009, 07:02		#3
tomislav_maric Senior Member Tomislav Maric Join Date: Mar 2009 Location: Darmstadt, Germany Posts: 284 Blog Entries: 5 Rep Power: 21	Hello, I'm using Salome-MECA and Engrid for meshing ships. I believe that Salome-MECA is really strait forward to use, especially for internal flows. You just import the .stl file, create the geometry groups if you want (it speeds up the meshing process), mesh first the solid in 3D, then use submeshing to refine the original mesh. You can download it from here: http://www.caelinux.com/CMS/index.ph...d=46&Itemid=40 The installation is non-existant, you just execute ./runSalomeMeca in the local dir for a quick look and work, but later just source the lib and bin dirs and it runs perfectly. SALOME doesn't edit .stl file, but there is absolutely no need. You explode the .stl into solid, face and edge components and build on that, adding perhaps additional geometry. You can have i.e. a railway car in the geometry module, but if you mesh just one plate, only that mesh gets exportet later. Conversion to FOAM is really easy. SALOME doesn't use metrics, so draw in meter dimensions, although scaling in OpenFOAM is really easy. Yes, and when you add groups to the mesh, you assign the names. These names get exported as bcs in .unv file and through conversion to OpenFOAM mesh. Hope this helps, Tomislav