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Andy R April 29, 2008 14:03

Surface Repair for Meshing
 
Folks, We normally run classes of problems with tractable bottom up geometry which we mesh in a straightforward fashion using Gridgen, ICEM or Gambit as appropriate.

We are now running into problems where we get cad geometry which is simply not going to work out of the box. These are underhood, external aero type problems but they are not automotive. Cant say more.

As an ex-adapco Prostar user, I would have used ProAm or whatever its called now and wrapped the surface to get a contiguous surface for meshing.

Whats the state of third party tools that perform these sort of functions? I see that ANSA is still a playere here. Any other tools that can do this? Any that are cheap or free ;-)

Thanks - Andy

Will April 29, 2008 15:44

Re: Surface Repair for Meshing
 
the star-ccm+ wrapper is very good for this kind of stuff, we use it to prepare full underhood geometries, it is a lot lot easier to use than proAM too..

Alex April 29, 2008 16:35

Re: Surface Repair for Meshing
 
on a related note for Andy, is your software now capable of unstructured stuff or tets? i remember a while back it was structured cartesian....

Andy R April 30, 2008 10:49

Re: Surface Repair for Meshing
 
For low speed stuff we use fluent, so when we need to we can run a tet mesh - Andy

myron April 30, 2008 11:02

Re: Surface Repair for Meshing
 
I believe ICEM also has a 'wrapper' - Look under Geometry > Create/Modify Surface > Geometry Simplification.

Chris April 30, 2008 12:32

Re: Surface Repair for Meshing
 
Gridgen has a capability called quilts and solid modeling.

paulh April 30, 2008 18:01

Re: Surface Repair for Meshing
 
Check out Materialise from 3-Matic or Harpoon from Sharc. Both will wrap - Harpoon will also give you a fluid grid. I have no experience with Materialise - I've just seen the advertisements. Harpoon was pretty good when I looked at it. CCM+ is very good. Hypermesh is also very good at cleaning up, and even making simple, geometry. Its surface mesh is pretty good as well.

paulh

BastiL May 1, 2008 16:10

Re: Surface Repair for Meshing
 
ccm+ wrapping is pretty good but volume meshing is poor....

Will May 1, 2008 16:56

Re: Surface Repair for Meshing
 
I disagree, the volume meshing is great if you know what you are doing, what do you mean by poor?

BastiL May 2, 2008 03:52

Re: Surface Repair for Meshing
 
For more simple geometries maybe... For really complex ones I have to remove thousands of "invalid" cells to get it running. However, sometimes it fails. Take the mesh to ProSTAR 4 and search for concave or centroid cells - in really complex geometries (full cars) you will find lots of poorely shaped strange looking cells. This happens for both Polyhedral and trimmed meshes. Tetra is ok.

Will May 2, 2008 13:29

Re: Surface Repair for Meshing
 
How odd, I have never had that many problems and I have wrapped and volume meshed full underhoods, are you sure you are using the latest version?

BastiL May 3, 2008 09:09

Re: Surface Repair for Meshing
 
No longer. We have switched to other codes. However, we saw that problems up to version 2.08. Did you check your mesh? ccm+ has a very stable solver and sometimes runs on theses dirty meshes.... Seems like some internal solver tricks to handle theses cells....

Will May 3, 2008 12:53

Re: Surface Repair for Meshing
 
The meshing did take a step forward after 2.08, there is also a bad cell treatment option now, the hex mesher is really quick


BastiL May 3, 2008 14:33

Re: Surface Repair for Meshing
 
I can not try anymore. We went to another tool which we are more happy with. I no longer have ccm+ licences.


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