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huey1080 March 5, 2012 15:56

CGNS Mesh Importation into ICEM
I am currently trying to import a CGNS structured multiblock mesh into ICEM CFD. But I am having a problem with the topology since ICEM seems to not find it. I have an error message that the topology is absent and proposes to recompute it. So I succeed in importing the mesh but the real problem is that when I am under ICEM, the mesh is in 1 block and the part are not separated (like Symmetry plane, farfield, etc..). I only have 1 part with every cell in it. Here is a screen of what I have under ICEM :

As you can see the 5 domains are well recognized in the tree but not separated. It is only the part named default and it is impossible to assign boundary conditions.

- I have also tried to import the mesh into CFX and the result is better since CFX separates the domain and the faces to allow the assignment of boundary conditions. Through that way I have exported the cfx-pre-case and try to import it under ICEM or Fluent but it gives me degenerated faces and I do not know why ?!

Here is the mesh under CFX which is editable :

Is there a way to import a CGNS into ICEM by separating every faces? Or do you know something that can unstuck me since I am running out of ideas to read this mesh !

Thank you very much

huey1080 March 14, 2013 13:34

To reply to those who have the same problem has me, the only way that I found to bias the problem is the following :

- In the CFX window (posted above) select each face that you want to be in the same part
- Apply a CUSTOM boundary condition with a specific name (I made this a long time ago so I do not exactly remember)
- Do this for all the parts that you want to have
- Save as a CFX-pre case which can be imported under ICEM

For my case I did not apply boundary conditions on internal faces this I did not required a multiblock mesh but an unstructured one but I think it is possible to do this for every face and under ICEM separate the mesh with the given faces because under ICEM every cells will be in the same part, I did not find a way to export directly a multiblock mesh !

I hope this will help you guys !

Good luck

sstemptation April 25, 2013 10:53

Problem in importing CGNS file to FLUENT
Hi 1080,

recently I met a problem when I import CGNS file into ANYSYS FLUENT 13.0. The CGNS file I imported is written by my own code, which use CGNS AIP.

The problem is that the CGNS file imported into FLUENT shows that no boundary condition exits in FLUENT and the error message is "Read_cgns_var: out of memory."
Mesh is right, but I just don't know why there is no boundary condition in it.
- I used CGNS AIP: such as cg_boco_write(..), like the examples shows.

And I try to import the same CGNS file into Tecplot, which shows that mesh and Boundary conditions are all right.

I hope you can help me find this problem out.



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