[Commercial meshers] starCCM+ to OpenFOAM mesh

giordy · January 13, 2016, 11:43

Hi All,

I am interested in the transferring between starCCM+ and OpenFOAM meshes. I did successfully for simple geometry but I got issues for complex ones. I read in an old Thread that:
"Also, the polymesh that Star creates is not always great quality. The solver can handle it because it just turns off those poor quality cells (just doesn't solve them) if they start to be a problem."

I exported a ccm mesh that it was running in starCCM+. When I used ccm26toFoam to import in OpenFOAM I get very bad cell quality and wrong oriented faces (by checkMesh). I tried also to import the mesh from starCCM+ to Fluent and the mesh check (in fluent) shows similar issue (for orthogonal quality and aspect ratio). Hence I was wondering if what I read in the old thread is true and If there is away to transfer a good quality mesh from starCCM+ to OpenFOAM.

thanks!
regards,
Stefano

agarwa58 · January 21, 2016, 20:25

Hi stefano,

I have faced similar problems in converting ccm+ mesh to OpenFOAM formats. There are always some cells of poor quality that lead to solver crashing in very initial iterations itself. The conversion works sometimes on relatively simplified geometries but even then this process is not very reliable. After a few attempts on different geometries, I stopped making further efforts in this direction and now use cfMesh for most of my meshing tasks.

Thanks,
Pulkit

giordy · January 22, 2016, 03:04

hi Pulkit,

I tried polyhedral cells and now i am trying tetrahedral cells. With polyhedral worked on simple geometry as you said. The problem is also that from the quality report i couldn't see the issue in starccm+ while it was evident in the quality check in openfoam. For this reason i did not know if to blame starccm+ or the converter (ccm26tofoam). I will let you know if i find a way. thanks.
Stefano

agarwa58 · January 25, 2016, 09:48

Hi Stefano,

This apparent difference in quality check might be due to the fact that ccm+ solver is more capable of handling cells of poor quality whereas the oepnfoam solver is a bit stringent on the quality check as it can operate on good quality cells only. Also, the converter ccm26tofoam poses some limitations with regards to mesh conversion for complex geometries. Nevertheless, I appreciate your effort to continue in this direction. Will be great to hear back from you if you find a way.

Thanks,
Pulkit

January 13, 2016, 11:43	starCCM+ to OpenFOAM mesh	#1
giordy New Member stefano zinna Join Date: Mar 2009 Posts: 29 Rep Power: 17	Hi All, I am interested in the transferring between starCCM+ and OpenFOAM meshes. I did successfully for simple geometry but I got issues for complex ones. I read in an old Thread that: "Also, the polymesh that Star creates is not always great quality. The solver can handle it because it just turns off those poor quality cells (just doesn't solve them) if they start to be a problem." I exported a ccm mesh that it was running in starCCM+. When I used ccm26toFoam to import in OpenFOAM I get very bad cell quality and wrong oriented faces (by checkMesh). I tried also to import the mesh from starCCM+ to Fluent and the mesh check (in fluent) shows similar issue (for orthogonal quality and aspect ratio). Hence I was wondering if what I read in the old thread is true and If there is away to transfer a good quality mesh from starCCM+ to OpenFOAM. thanks! regards, Stefano

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January 21, 2016, 20:25		#2
agarwa58 New Member pulkit Join Date: Jun 2013 Posts: 5 Rep Power: 12	Hi stefano, I have faced similar problems in converting ccm+ mesh to OpenFOAM formats. There are always some cells of poor quality that lead to solver crashing in very initial iterations itself. The conversion works sometimes on relatively simplified geometries but even then this process is not very reliable. After a few attempts on different geometries, I stopped making further efforts in this direction and now use cfMesh for most of my meshing tasks. Thanks, Pulkit

January 22, 2016, 03:04		#3
giordy New Member stefano zinna Join Date: Mar 2009 Posts: 29 Rep Power: 17	hi Pulkit, I tried polyhedral cells and now i am trying tetrahedral cells. With polyhedral worked on simple geometry as you said. The problem is also that from the quality report i couldn't see the issue in starccm+ while it was evident in the quality check in openfoam. For this reason i did not know if to blame starccm+ or the converter (ccm26tofoam). I will let you know if i find a way. thanks. Stefano

January 25, 2016, 09:48		#4
agarwa58 New Member pulkit Join Date: Jun 2013 Posts: 5 Rep Power: 12	Hi Stefano, This apparent difference in quality check might be due to the fact that ccm+ solver is more capable of handling cells of poor quality whereas the oepnfoam solver is a bit stringent on the quality check as it can operate on good quality cells only. Also, the converter ccm26tofoam poses some limitations with regards to mesh conversion for complex geometries. Nevertheless, I appreciate your effort to continue in this direction. Will be great to hear back from you if you find a way. Thanks, Pulkit