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Astrid December 18, 2001 18:06

2D in CFX 5.5 (2)
Hi all again,

In search of a route to a decent 2D-grid in CFX 5.5, the next chapter:

I have been able to create a suitable 2D-grid in CFX 5.5 using the MESH-only mode and the PATRAN-mesher. I exported the unstructured HEX-mesh in NEUTRAL format. Then I imported the grid again in CFX 5.5. Everthing works fine so far. However, somehow I am not able to define patches (e.g. inlets, walls). Not in the MESH-only PATRAN-mode (as the NEUTRAL-format does not contain patches) and not after I have imported the grid (as the imported grid remains frozen). Does anyone know how to define these?

Thanx for reading, Astrid

Robin Steed December 19, 2001 00:22

Re: 2D in CFX 5.5 (2)
Hi Astrid,

While you are in the Patran volume mesh mode, create mesh groups (using the groups feature) to define boundary patches. Then export your mesh.

Incidentally, you can make a really nice 2-D hex mesh using the paving tool, then extruding it. The same tool can also be used to sweep out a paved surface, along a pipe for instance.

Regards, Robin

Astrid December 19, 2001 03:21

Re: 2D in CFX 5.5 (2)
Hi Robin,

- Thank you for the tip. I will try it today.

- Indeed. I have created a nice 2D-unstructured hex-mesh on a symmetry plane and then extruded it in z-direction using the sweep tool. Step 2 is to associate the obtained volume mesh to the Solid. is it somehow possible to extrude a tet-mesh on a surface to a volume mesh with only prisms (wedge6)????

Thanx, Astrid

Robin Steed December 19, 2001 20:59

Re: 2D in CFX 5.5 (2)
Hi Astrid,

No need to associate it to a solid, just create the necessary mesh groups for your boundaries, then export the mesh in the Patran neutral format. You must then start a new database, selecting the "Import Mesh" feature this time.

Regards, Robin

Astrid December 20, 2001 08:46

Re: 2D in CFX 5.5 (2)
Hi Robin,

- It worked. Thanks a lot.

- You didn't answer my second question: can you extrude a tet surface mesh to a 2D wedge volume mesh?

Regs, Astrid

Robin Steed December 21, 2001 01:09

Re: 2D in CFX 5.5 (2)
Hi Astrid,

It is possible to do this. You will have to contact your technical support representative at CFX to get an additional meshing executable and setup details.

As far as the mesh goes, you can make a better quality mesh by doing exactly as you have done. The only advantage you will gain by creating a 2-D mesh with the CFX mesher is when adaption is used; if you use the automatic adaption on an imported mesh, it will not adapt to your geometry, whereas if you meshed it with the CFX mesher, new nodes at your boundaries will snap to the original geometry.

Best regards, Robin

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