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rvs October 12, 2010 10:53

creating interfaces in ICEM
Hello All,

I want to run a CFD calculation in CFX with mesh generated from ICEM. I have problems in applying BC to my model, the following is the description of the problem -

1. I imported a CAD geometry with surfaces and created a surface mesh as required and extruded the surface mesh with the required number of elements in the Z direction.

2. I imported the mesh into CFX, and now comes the problem. i am trying to apply BC along the interface boundaries through the model, but unable to do so as I cannot select a particular surface in the Z direction.

I guess the problem is from my extrusion method, since the extrusion allows to name the volume, side and top and if the does not allow to name/separate each surface of the extrusion.

I am not able to figure out how to separate the faces/surfaces and name them accordingly and select them to apply my BC. Can anyone help in this step, if this is possible to separate the surfaces after creating a 3D mesh.

I am not considering a 3d model because the model is very huge in Z direction.

Hope someone can help me with this.

Thank you,

csmith_PADT October 12, 2010 15:51

In order for CFX to recognize the (interior) surfaces associated with the extrusion of your surface mesh so that you can apply boundary conditions there, you will need to create separate parts for each extrusion level in your ICEM model.

rvs October 13, 2010 10:51

Thank you csmith_PADT, I have tried doing what you have just mentioned, But the problem seems to persist. Let me explain what happens when I try the method you have mentioned:

I extrude the surface mesh for each surface separately and then say I want to choose one of the surfaces/faces of the 3D model just created, I click on one face of an element on the face I want to create the part. Then since I need the entire surface in Z direction I select "select all items attached to the current selection" (I cannot select each and every face of a element because my model is 3.4m long, so there are around 226 elements along the length) now at this point what ICEM is doing is it chooses the 3D element i.e 1 element in thickness on the surface i want to create, But I only want the face and not the volume elements attached to the surface.

I tried other option of extracting the surfaces along a curve, and then create a part out of it. It did work in ICEM, but I am not able to see this being defined as a 2d region when I import it to CFX-pre.

I am not sure how to proceed further.

csmith_PADT October 13, 2010 11:29

A question for you: why are you trying to define interfaces in the mesh at every extrusion level? Do you have different physics or moving domains applied in each successive extruded "zone"?

If this is the approach you want to follow, you will need to create separate material points for each extrusion level, as this is a critical step in defining separate parts in ICEM.

galap October 14, 2010 03:56

I'm not sure if I understand you correctly, but as I was dealing with similar problems I give you my thoughts.

I seperate the surface parts for extruded meshs by extracting the shells by "Add to part -> Select mesh attached to geometry" and then choosing the respective surface. If volume elements were added wrongly, I put them in the right part by selecting all volume elements.

Karatix October 14, 2010 16:44

Hi Everybody,

I had similar problems. The way I did it was to set up the problem as 2D with the blocking !!! method.
Afterwards I extruded the blocks and associated the faces to the surfaces. This way you are able to select boundary conditions.

Good luck,


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