Netgen Meshing Problem

[mk277]

Hello,

I'm using Elmer a couple of weeks, with good results with some basic models.

Now I build a basic model of a cooling plate with a pipe (see attatched Image) in Inventor and I want to mesh it in Netgen.

Now to my problem: when I want to mesh the model (Step-File) in Netgen, I get the following error: "SYSTEM ERROR: more elements on face".
When I use "Check Surfache Mesh", I get a couple of errors, like:

Code: Select all

 WARNING: Intersecting elements 2366 and 104
el1 = np = 3 1217 155 1292
el2 = np = 3 294 262 287
layer1 = 1
layer2 = 1

Does anybody know how to solve my problem or where my mistake is?

I'm using Windows 7 Professional 64Bit.

Greetings,
Markus

[mzenker]

Hi,

you might have the "duplicated interfaces" problem: If two bodies share a common surface, you get a duplicated mesh on the interface which causes problems with 3D meshing and does not let heat flow between the bodies. If you use netgen, you might try the healing feature, but this does not always work, especially for curves surfaces as you have here. Or you can try to import the step file in gmsh, save in .geo format and repair the conflicting surfaces by hand (in brief: delete volumes, delete the duplicated surfaces, rebuild the volumes).

HTH,

Matthias

[mk277]

Thank you for your fast reply.

If you use netgen, you might try the healing feature, but this does not always work, especially for curves surfaces as you have here.

I had already used the healing feature in netgen, unfortunately it doesn't work.

Or you can try to import the step file in gmsh, save in .geo format and repair the conflicting surfaces by hand (in brief: delete volumes, delete the duplicated surfaces, rebuild the volumes).

Is there an example or tutorial for? I have yet not work with gmsh. I found only examples to build new objects.

Greetings,
Markus

[mzenker]

Hi Markus,

there is no specific example for this problem that I know of. You can find a reference manual and a link to the gmsh mailing list on the gmsh web site http://www.geuz.org/gmsh. Just play around a bit with a small geometry and try to understand from the .geo file how it is built.
I have just thought that in your geometry, one body is completely inside the other. What you could do is export just the outer body in step format with the hole and build a volume inside the hole, that should be easy.

HTH,

Matthias

[mk277]

Thank you Matthias for your help.

I will test gmsh and hope I can solve my problem.

Greetings,
Markus