[aut_iut]

Hello everybody!

I wanna export the meshes from Comsol multiphysics to the openfoam!
Is there any straight solution for me?

Thanks

[sega]

Originally Posted by aut_iut

Hello everybody!

I wanna export the meshes from Comsol multiphysics to the openfoam!
Is there any straight solution for me?

Thanks

I can't think of a "straight" solution.

COMSOL can export the mesh to text (*.mphtxt) or binary (*.mphbin) files.
If you look at these files you will see they contain all mesh points and further informations concerning the elements.

Maybe the element informations are usefull to tell OpenFOAM how to make cells out of them (OpenFOAM is a finite-volume-code and COMOLS is a finite-element-code).

You will have to do the link between all COMSOL mesh points and the OpenFOAM mesh. Don't think of something blockMesh-stylish - look at the mesh files you will get after the mesh is created from the blockMesh.

Keep in mind that OpenFOAM only supports 3D-cartesien meshes and COMSOL supports far more!

[niklas]

Originally Posted by sega

Keep in mind that OpenFOAM only supports 3D-cartesien meshes and COMSOL supports far more!

eeh...wrong.
foam can handle any type of mesh.

[sega]

Originally Posted by niklas

eeh...wrong.
foam can handle any type of mesh.

He is right. Let me put this straight.
COMSOL supports other solvers than 3D cartesian and the meshes are adapted to the solver.

[franzi_]

Hello,

the reply didn't really help me so I hoped that maybe somebody can give me any good hints if it is possible to convert meshes from Comsol to OpenFoam???

Is it even possible to convert from FEM to FVM mesh?

I would be really glad about any kind of hint or experiences on that topic!!!!

Thanks a lot in advance!

Cheers, Franzi

PS: I tried to mesh also with Salome but the program isn't really stable. Any hints for a better mesher would be helpful, too

[elvis]

Hi,
http://www.uk.comsol.com/products/formats
shows that sections Mesh & MCAD is poor for export
File Format Read Write
NASTRAN Bulk Data (.nas, .bdf, .nastran, .dat) Yes No
VRML, v1 (.vrml, .vrl) Yes No
STL (.stl) Yes No
STEP (.step)2 Yes No
IGES (.iges)2 Yes No
CATIA® V5 (.CATPart, .CATProduct)5 Yes No
VRML, v1 (.vrml, .vrl) Yes No
STL (.stl) Yes No

It depends on what you are looking for! Opensource: engrid or http://www.discretizer.org/

[aujamal20]

Hey Foamers,

Have anyone of you guys succedded in importing geometry files from Comsol to OpenFOAM..... I will be doing that stuff very soon. Looking for hint and thanks in advance.

Thanks

Jamal

[wouter]

Hello aujamal20,
Last year I have written a program loosly based on cfx4toFoam that can read a comsol 4.2a mphtxt or mphbin file and convert it into an Openfoam mesh. To get the boundary names you need to make a reportfile (.html) in comsol, minimum is geometry, mesh units I think ( a full report is the best thing).
It can read 3D and 2D and axial meshes.
There is a warning that the boundaries are all going to the default, this is not true but I did not know how to prevent this warning.
The program is not finished, domains are all merged to one domain.
The boundary information for the 0 directory is not yet collected.
This project of mine is stopped because I do not have access to Comsol anymore, so I do not know if it works with newer Comsol versions.

http://www.filedropper.com/comsoltofoamtar

just unpack files in a source directory (eg OpenFOAM/user-xxx/run/applications/utilities/mesh/conversion/comsolToFoam )
run wmake.
(NB. Because I did not plan to publish this I did not use the OpenFoam conventions for programming. I am very old school so part of it is c not c++ ).
Hope you can use this, let me know if you can improve the program.
Best regards
Wouter

[Prosper]

Originally Posted by wouter

Hello aujamal20,
Last year I have written a program loosly based on cfx4toFoam that can read a comsol 4.2a mphtxt or mphbin file and convert it into an Openfoam mesh. To get the boundary names you need to make a reportfile (.html) in comsol, minimum is geometry, mesh units I think ( a full report is the best thing).
It can read 3D and 2D and axial meshes.
There is a warning that the boundaries are all going to the default, this is not true but I did not know how to prevent this warning.
The program is not finished, domains are all merged to one domain.
The boundary information for the 0 directory is not yet collected.
This project of mine is stopped because I do not have access to Comsol anymore, so I do not know if it works with newer Comsol versions.

http://www.filedropper.com/comsoltofoamtar

just unpack files in a source directory (eg OpenFOAM/user-xxx/run/applications/utilities/mesh/conversion/comsolToFoam )
run wmake.
(NB. Because I did not plan to publish this I did not use the OpenFoam conventions for programming. I am very old school so part of it is c not c++ ).
Hope you can use this, let me know if you can improve the program.
Best regards
Wouter

This might be helpful! Worth a try!

[6863523]

Originally Posted by Prosper

This might be helpful! Worth a try!

Dear Prosper,
Have you succeeded in importing the comsol files into openfoam? I am trying, but without any progress.
Would you please give me some help?
Thank you in advance.
Best Regards,
Bill

[wouter]

Hello Bill,
As I told you it is for version 4.2b of comsol, I do not remember what version of OF (I think OF2.2.0).
I still have no access to comsol anymore so I cannot update the software, but the C file will give you a start to find where it goes wrong.

Best regards
Wouter

[6863523]

Originally Posted by wouter

Hello Bill,
As I told you it is for version 4.2b of comsol, I do not remember what version of OF (I think OF2.2.0).
I still have no access to comsol anymore so I cannot update the software, but the C file will give you a start to find where it goes wrong.

Best regards
Wouter

Dear Wouter,
Thank you for the reply. I will have a try on COMSOL 5.2a and OpenFOAM 3.0.1 and then I will let you know.
Thank you for your hard work.
Best Regards,
Bill

[Minisasi]

Bill any luck?

[6863523]

Sorry, not yet.
I am using Salome to mesh for OpenFOAM simulation.

[Minisasi]

Well then, do you think it is possible to import a mesh from comsol to salome ?

[wouter]

hello Minisasi,
Did you try to run my program? It compiles under OF-dev. It also runs under OF-dev with a file from Comsol 4.2a.
Can you send me a Comsol file .mphtxt and a report .html (preferably a simple geometry for testing). Maybe I can find out why it does not work.

Hope this helps
Wouter

[Minisasi]

Hi Wouter, thank you for your reply,
I am actually using Comsol 5.2 and OF-2.3.1 (this might be the problem).
The error I am getting is:

--> FOAM FATAL IO ERROR: 
wrong token type - expected int, found on line 4721 the word '#Geometric'

file: meshSimple1.mphtxt at line 4721.

    From function operator>>(Istream&, int&)
    in file primitives/ints/int/intIO.C at line 68.

FOAM exiting

I attached the mphtxt and the html file (It is a very simple rectangular test case)

Thanks for your help

[wouter]

Hello Minisasi,
I have reproduced the problem. Comsol has changed the structure of the meshfile. I will try to solve this.
Thanks for this simple mesh. It is not so simple for OpenFoam, because it is a 2D or 2DAxi mesh, is it possible you send me a 3D mesh?

Best regards
Wouter

[Minisasi]

Hi,
Yes, you are right about OF. Plus, I don't know Comsol very much, but it doesn't look to be very friendly in terms of importing/exporting mesh. I don't have a 3D test case at the moment. Let me know if you end up with a possible solution.
Alternatively I can export the mesh from Comsol in .txt or .nas or .bin, but I cannot find a way to let OF reading those format.

Any help is much appreciated,


Thank you again for your time.

[wouter]

Hello Minisasi,
The program can read the .mphtxt and the .mphbin. But there are some changes and I had some apointments so little time, work also consumes a lot of spare time. But I do my best. A 3D mesh would help to check the program. Maybe someone can send me a 3D mesh of a cube with 64 cells.

Best regards,
Wouter