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-   -   Geometry and meshing with CFX (http://www.cfd-online.com/Forums/cfx/20069-geometry-meshing-cfx.html)

Bob Crad December 25, 2003 01:52

Geometry and meshing with CFX
 
I am in a process of choosing a CFD package for a coming task where centripetal body forces will be considerable. To my knowledge, SSG model is the best one for rotating domains. That is, particularly, why, CFX seems to be suitable for me.

My concern is, however, the rumours are CFX geometry builder is not very strong and even unstable for real geometries (even if they are not extremely complicated).

Another issue is CFX Build generates only unstructured TET-grid (and prisms for boundary layer), I was told. Well, I would prefer to have a HEX generator.

There is a wide-spread opinion it is impractical to take GEOM-, MESH-, SOLVER and POST from different sources.

That is why, I would like to get you opinion on using BladeGen to make, say, a blade similar to that off a turbocharger blower wheel and then to use TurboGrid to create a good mesh.

Other words, what sort of pre-processor(s) CFX users employ in practice?

Thank you and cordial regards

Bob Crad

derrek December 30, 2003 09:45

Re: Geometry and meshing with CFX
 
Bob:

ICEM CFD HEXA works very nicely for creating hex meshes with CFX. In fact, they are both owned by the same parent company, ANSYS. HEXA has direct plug-ins to many of the standard CAD packages. You have to decide whether the geometry will be built from scratch or whether you have existing CAD geometry.

If you need to build the geometry from scratch, ANSYS/CFX has a very nice geometry creation tool, Design Modeler. It is very reasonably priced and has some nice tools that are desiged for the analyst.

If you are content with tet/prism, there is a bundle available called CAD2MESH, that combines Design Modeler and ICEM Tetra/Prism with a new improved GUI.

Anyway, there are some other options as well. Feel free to email me with questions.

Regards,

Derrek

Glenn Horrocks January 4, 2004 18:20

Re: Geometry and meshing with CFX
 
Hi Bob,

(In addition to what derrek said):

CFX-Build is no longer available, so forget about its weaknesses. If you purchase CFX5 you will get ICEM CFD 4.CFX as the preprocessor. I strongly disagree that the CFX pre-processor is "not very strong and even unstable for real geometries". I think you will find the new ICEM (including the hexa option) meshing tools to be some of the best available. Of course, you should trial it on your geometry before you purchase it to make sure you are happy with it.

CFX imports meshes from most meshing packages (including many formats from outside the ANSYS empire). This means if you don't like the CFX mesher but want to use the solver you can easily use your preferred meshing software and import into CFX.

Glenn

Bob Crad January 7, 2004 13:56

Re: Geometry and meshing with CFX
 
Yes, Glenn, thank you very much for your reply. I have had a chat with a CFX User who just bought CFX 5.6 with CFX-Build in it. He told there is a 1500-page CFX-Build help book there. (He is a beginner and does not have his own judgement on CFX.) Thank you again for you sharing your experience.

Bob


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