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-   -   Which Meshing software can I use? (http://www.cfd-online.com/Forums/su2/120797-meshing-software-can-i-use.html)

shsreekanth July 15, 2013 06:03

Which Meshing software can I use?
 
Hi,
I am familiar with Meshing in GAMBIT. The meshes created are in .msh format.
But SU2 requires the mesh to be in .SU2 format or .CGNS format. Is there a way to convert the mesh generated in GAMBIT to CGNS format?
If not, can you tell me another suitable meshing software.

I tried EnGrid, but it requires another CAD software for geometry creation. The website suggested Blender for this. I tried Blender 2.6, but it doesnt have an option to export the geometry in .begc format as required for EnGrid. EnGrid website says it accepts .stl format, but when I try to import anything in .stl format in Engrid, it crashes (Fedora 16).

shsreekanth July 16, 2013 06:14

I know to generate boundary layer mesh in GAMBIT. I tried one, exported it in CGNS format using fluent. But when SU2 reads the mesh it throws an error.
"!!! Error !!! Unrecognized element type."

The same error does not occur if there is no boundary layer mesh. How can I get around this problem

onyir July 17, 2013 03:19

Quote:

Originally Posted by shsreekanth (Post 439773)
I tried EnGrid, but it requires another CAD software for geometry creation. The website suggested Blender for this. I tried Blender 2.6, but it doesnt have an option to export the geometry in .begc format as required for EnGrid. EnGrid website says it accepts .stl format, but when I try to import anything in .stl format in Engrid, it crashes (Fedora 16).

Hi,

To be able to export in begc format from Blender you need to install the proper addon. The addons it's in the engrid installation directory. To install it in Blender, in the user preferences, click on Install from file... and select file in engrid folder

shsreekanth July 17, 2013 14:27

Thank you onyir, I got the "export to engrid (*.begc) " option now in Blender

kiski July 22, 2013 04:26

Quote:

Originally Posted by shsreekanth (Post 439773)
Hi,
I am familiar with Meshing in GAMBIT. The meshes created are in .msh format.
But SU2 requires the mesh to be in .SU2 format or .CGNS format. Is there a way to convert the mesh generated in GAMBIT to CGNS format?
If not, can you tell me another suitable meshing software.

I tried EnGrid, but it requires another CAD software for geometry creation. The website suggested Blender for this. I tried Blender 2.6, but it doesnt have an option to export the geometry in .begc format as required for EnGrid. EnGrid website says it accepts .stl format, but when I try to import anything in .stl format in Engrid, it crashes (Fedora 16).

Hi,
I have also been working for a while with blender and engrid in order to create meshes for SU2. But after a while I found it difficult to work with because working with .stl is not as easy as working with a CAD file if modifications has to be done. Additionally, I found some errors when running meshes with prisms created by Engrid. The simulation reports something about "negative pressure..." for very simple and curved geometries.

In short, I decided to move to Salome-platform. I find it good enough to work with my geometries. You can actually create the CAD and the grid with this software. I am very happy with my new option. However, you cannot export to .SU2, but you can export .unv to gmsh, from here export again in .vtk to engrid, and in engrid define boundaries and export to .su2.
I used to work like this for a while. Now I am just mastering Salome and I created my own scripts to export from Salome to .SU2 directly. And meshing velocity of Salome is just much faster than Engrid.

Hope it helps

shsreekanth July 22, 2013 04:54

Thanks kiski for a timely reply.
Since I am just getting started, it really helps to find the better option and proceed with that. I am not familiar with Blender or Engrid and now that I know its drawback, it saves me time.
Will give a try to Salome. Also, I hear that Larosterna mesh generator now has option to export in SU2.

kiski July 22, 2013 04:59

I never heard about Larosterna. But it is good to know it exists :-)
About salome, if you are using Linux, it is easier if you install the "universall binaries", other options gave me hard time trying to compile!!

shsreekanth July 22, 2013 05:05

Hi Kiski,
Thanks for the tip. How did you export directly to .SU2 from Salome ? Can you share?

kiski July 22, 2013 05:33

Hi shsreekanth,
I am modifying a lot the script I use until I get a final version, which will take me a while since I am working in other things as well. However, you can have a look in this forum in which I posted a script for unstructured meshes with prisms.

If I remember well, it exports the first mesh entry (in case you have more than one mesh computed), and the boundaries of the .su2 file are the "mesh groups" within the mesh you created in Salome. The way to work is, once you have the mesh you want to export, in salome Load the file in the post through the Salome menu and it will export your mesh to your $home directory. Have a look to the code of the script, because it is pretty simple and you can adapt it yourself.

shsreekanth July 22, 2013 05:40

Thank you. I will try that

shsreekanth July 22, 2013 06:40

To get around the error - "Unrecognized element type"- this thread deals with it http://www.cfd-online.com/Forums/su2/113393-cgns-grid-problem.html

shsreekanth July 22, 2013 06:41

Larosterna can be found here http://www.larosterna.com/index.html

kiski July 22, 2013 06:48

thanks for sharing all this. About the "Unrecognized element type" y wrote it in the file only to mention that I didn't make "write to file" sopport of this element type. For example, hexas are not included in my script although there is no problem in .su2 or Salome. It just has to be included in the script as it was included for tetras

rktchip July 25, 2013 12:46

Quote:

Originally Posted by kiski (Post 441157)
Now I am just mastering Salome and I created my own scripts to export from Salome to .SU2 directly. And meshing velocity of Salome is just much faster than Engrid.

Hey kiski,
would you mind sharing your export scripts with the community? These would be very cool to see!
- Trent

kiski July 27, 2013 12:06

Hi rktchip,

Look in the post entry #9, I am modifying the scripts in order to have only one script for any kind of mesh. But now I am in holidays XD. In entry #9 you have a script which works


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