Meshing the flow but not the pipe

Mesh generators, CAD programs, and other tools
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Gary R
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Joined: 12 Apr 2012, 07:23
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Location: Long Beach CA, USA

Meshing the flow but not the pipe

Post by Gary R »

Hi all,
I have been trying to mesh the air inside of a pipe (iges attached). The pipe was created with FreeCAD. I have gmsh and Netgen and have tried both. I seem to be missing something. The general problem is how to mesh voids. I have thought about putting end caps on the tube but have tried to mesh completely enclosed objects with no luck. The ElmerGUI manual is no help because all of the examples come already meshed. Please keep it simple and detailed if possible. Some of the terminology throws me.

Gary R.
VentTube.iges
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kevinarden
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Re: Meshing the flow but not the pipe

Post by kevinarden »

You have surfaces, to get solid elements you need volumes. You would put end cap surfaces on the pipe. You would then use the inside surface of the pipe and the two end caps to make a volume. You would then use the outer surface, inner surface, and two pipe end surfaces to make a volume for the pipe.
kevinarden
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Re: Meshing the flow but not the pipe

Post by kevinarden »

Or easier was to go into FreeCAD's part workbench and work with 3D parts. Created cylinder using primitive. Made a second cylinder to cut first cylinder into a pipe using boolean cut. Created 2cnd cylinder for the fluid. Used make compound to join the pipe and fluid into one part. Export cad to step file. Import step into gmsh, mesh, save mesh. Open in ElmerGUI.
pipe.msh
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pipe.step
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Gary R
Posts: 108
Joined: 12 Apr 2012, 07:23
Antispam: Yes
Location: Long Beach CA, USA

Re: Meshing the flow but not the pipe

Post by Gary R »

Thank you kevin,

Things finally clicked into place. You can't mesh nothing. I used the Part workbench and the pipe primitive. So there was nothing inside the pipe to mesh. Don't know why I didn't get this before. I guess I can blame it on my 6 month bout with vertigo. It's hard to think when you are dizzy all of the time.

Thanks again.
Gary R.
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