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-   -   Using Salome for mesh generation (http://www.cfd-online.com/Forums/openfoam-meshing-open/104529-using-salome-mesh-generation.html)

MatP July 11, 2012 13:59

Using Salome for mesh generation
 
Hey there!

Can anyone give me some hints about the capability of any Salome version to mesh an imported geometry with a hexahedral mesh?

Steven Chew August 23, 2012 10:26

Hi,

I am also looking for assistance regarding meshing in Salome.

I can't seem to find any information on implementing line/surface mesh sources. Is there any tutorial available regarding this?

I tried this site

http://www.salome-platform.org/user-...ome-tutorials/

but somehow my meshing process always fails.

elvis August 24, 2012 06:58

Hi,

http://www.salome-platform.org/user-...edf-exercise-1

http://www.caelinux.org/wiki/index.php/Doc:CAETutorials
=>4 Salome & OpenFOAM tutorial

maybe http://pythonflu.wikidot.com/hybridflu it is not 100% what you looking for (but at least salome and meshing)

One comment ideasUnvToFoam does not convert everything that is meshed in salome therefore some people use hybridflu

Steven Chew August 25, 2012 02:29

Thanks elvis. Will go and try it out.

Steven Chew August 27, 2012 07:51

Hi, I have tried following the pipe tutorial, but it actually does not have face sources. What it does is only uniform meshing applied across all the surfaces of the pipe.

I have tried exporting a simple cube using uniform mesh already, and it works in OpenFOAM. There shouldnt be any problem over there, but my real headache is finding any information on implementing mesh sources on geometrical faces. Any advice?

Steven Chew August 27, 2012 08:02

I am trying using this approach, but im not sure if it's right

Geometry
new entity -> primitive -> box -> 10x10x10 -> Box_1
Box_1 -> Create Group -> Face Type -> left click one side -> Add -> Apply and Close -> Group_1

Mesh
Box_1 -> Create Mesh -> Netgen 1D-2D-3D -> Netgen 3D Parameters -> Max 1 Min 0.05 Fineness Fine Optimize -> Mesh_1
mesh_1 -> Compute
mesh_1 -> Create Group -> Face type -> Group on geometry -> geometrical object -> direction selection -> Box_1 Group_1
mesh Group_1 -> edit Mesh -> Netgen 1D-2D -> Netgen 2D Parameters -> Max 0.5 Min 0.05 Fineness Fine Optimize -> Mesh_2
Right click Mesh_2 -> Compute

But it always hangs and fails.

MatP August 27, 2012 08:30

Hi Steven,

did you try to define the Sub-Meshes before computing the whole mesh? And you don't have to define new groups of faces in the mesh module but you can use those defined in geo-module. So after defined the global mesh define the sub-meshes (refinement ...) on the desired groups and once you've finished just press compute.

hope this helps..

Steven Chew August 27, 2012 09:05

Quote:

Originally Posted by MatP (Post 378883)
Hi Steven,

did you try to define the Sub-Meshes before computing the whole mesh? And you don't have to define new groups of faces in the mesh module but you can use those defined in geo-module. So after defined the global mesh define the sub-meshes (refinement ...) on the desired groups and once you've finished just press compute.

hope this helps..

I just tried to
Create a box, explode into its 6 faces.
Created a group consisting of just one face (Face 6)
Switch to mesh module, create a mesh from box, 1D-2D-3D, max 1, min 0.02
Create sub-mesh on Group, 1D-2D, max 0.5 min 0.02

I tried to click on the global mesh and Compute, the system failed
I tried to click on the sub mesh and Compute, the system failed

by the way, I'm using the Windows version of Salome 6

MatP August 28, 2012 02:06

Ok... i think the Windows Version may be the reason for your problem. I've had the same problem during testing the capabilities of Salome Meshing tools and when using Netgen for refining the meshing failed and Salome crashed. So try to use another algorithm or use a Linux distribution as working system.

MatP August 28, 2012 02:27

Hmm.. it seems as if there's a bug. I managed to create the mesh you wanted this way:

1. Create Box and group of face as you already have done
2. Create Mesh on box: Assign set of hypotheses -> 3D automatic Tethraedalization with a desired length of 1
3. Create SubMesh of face: Assing set of hypotheses -> 2d automatic triangulation
4. Compute SubMesh: now you can see the fine mesh on the face 6
5. Click on Mesh1 and compute it. Now the process should be successful and you have a mesh with a specific number of edges, faces and voumes.
(5.a it also should work if you just define both your meshes and then click on Mesh1 and compute the whole mesh at once)

But if you want to modify your created mesh or make it once again, the process crashes...

ShuToshio August 28, 2012 03:12

I've managed to do the refined meshing on one side using Linux Salome. Thanks for your help, man! :) or else I'd still be floundering in murky waters for god knows how many days, trying to figure out which step I've taken wrongly.

ShuToshio August 28, 2012 10:41

Well, meshing the cube was successful since the geometry is quite straightforward.

I then proceeded to mesh my real case (which happens to be a car).

- Created a box and did subtraction to derive the fluid domain
- explode into faces and grouped all car surfaces under one group, as well as walls and inlet outlet
- created a mesh under the domain
- created a submesh under the car surfaces

Both the domain mesh and car surface mesh I used automatic tet and triangles. but it constantly gave me error message

NETGEN_3D failed on sub-shape #1 with error COMPERR_BAD_INPUT_MESH "Intersecting triangles"

Algorithm: NETGEN_3D
Subshape: domain
Error: Invalid input mesh. Intersecting triangles

MatP August 30, 2012 01:46

And don't know the exact meaning of this error message but i think your problem comes from the definintion of your geometry. Maybe you've some double faces or faces with intersections points. You can find those faces after computing the mesh with an error message by clicking on the appearing information panel at show sub-shapes. Now you can see the faces appending to the error colored in your mesh display.

Maybe this could help you too:
http://www.salome-platform.org/forum/forum_10/912677133


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