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Ray March 14, 2000 13:24

merge meshes together
Hi! There,

I would like to generate grids for different zones using gambit, and later merge them together using gambit or tgrid.

Your advice will be highly appreciated.


Kai Kang March 14, 2000 14:04

Re: merge meshes together
I had the same idea, but the problem I had was the boundaries. Because gambit automatically use 'wall' for any surface unspecified, I used tfilter tmerge3d to merge the two zones generated from gambit and then in Fluent tried to fuse them together to make them one entity, but was failed somehow because the two faces I want to fused together was not completely conform.

I know interface would solve this,but I do not want go that way, because there are so many limitations on Interface, and for hex-grid I usually have subdivide my model to many blocks.

Do anybody have any idea to work around this in Gambit?

Jonas Larsson March 14, 2000 14:41

Re: merge meshes together
I've done this several times without problem - meshing one part in Gambit, deleting all but a face, and then continuing to mesh the other part on the other side of the face. I never had any problems to merge the two parts with tfilter tmerge3d and then fuse them together in Fluent.

Jurek March 14, 2000 15:47

Re: merge meshes together
I'd try this way: 1.load both meshes in tgrid 2.merge the nodes with increasing tolerance. Count the nodes before so you are sure that all went correct 3. Delete or change type of the resulting surface. 4. merge the two zones. I never had to try this but I think it should work. If not, correct me. Jurek

Kai Kang March 15, 2000 10:53

Re: merge meshes together
The face you left there when you mesh the other part insures the two parts has a common conformed face, I think, but sometimes, non-conformed face wouldn't fuse well in fluent, no matter how I adjust the tolerance value...

Shyam Kishor March 16, 2000 13:58

Re: merge meshes together
For a valid conformal mesh, mesh nodes on the faces at the interface of the two parts have to be matching within tolerance. Then, you can either merge the nodes (using Tgrid) or Fuse the zones (using Fluent). If you use Tgrid to megre the duplicate nodes, the resulting surface at the interface will have the boundary type as "wall" which should be changed to "interior" if both sides of the interface have same cell(fluid) zone. Fluent automatically convert the resulting surface after fuse to be of "interior" type if both sides of it has the same cell (fluid) zone.

Also, if you are not using Tgrid, you need to use tfilter tmerge3d to merge the meshes together before reading them into Fluent. Tgrid does the same when you load multiple mesh files at a time.

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