boundary conditions and mesh exporting
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1. I imported a BREP geometry into NETGEN 4.9.12 and meshed it. Now I'd like to set boundary condition codes, but I'm groping for the solution. If i select Edit Surface Mesh Size I can highlight the patches. I made a note of them, becouse I don't know how to rename them. I used Salome to build the geometry, can I define the name of the patches by it? Well, for the present I note their index. After meshed the geometry, I guess I must select Edit Boundary Conditions and set an appropriate number for the bc property (a strangeness: when I pass through the face index, only one face is red-lighted - and not always the same one).
2. After setting bc, have I to export the mesh in neutral format and then launch NetgenNeutralToFoam? I don't find this command in the OpenFOAM user guide. Please, help me with the correct procedure. UPDATE 1. A bug prevent the rendering window to update surface colours according to the selected boundary face 2. I can't define boundary surfaces in Salome but I note the index that NETGEN assign to and set boundary codes in order to assemble the patches. 3. I tried to export the mesh and its boundary conditions in two different ways but it doesn't work: a) I exported the mesh in OpenFOAM-1.5.x format but boundary file in polyMesh folder contains 6 patches (of 7 surfaces) and I expect 5 (I use OpenFOAM-1.6.x) b) I exported the mesh in neutral format but I have an error when I run netgenNeutralToFoam (but the number of patches seem to be right) Code:
giulia@giulia-laptop:~/OpenFOAM/giulia-1.6.x/run/blade$ netgenNeutralToFoam mesh/*---------------------------------------------------------------------------*\ |
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Hi
Looking at the geometry in Salome one thing comes to mind with my experience in generation of blade/propeller geometry. Create it at least with two faces. You only have one face for the whole blade. split it so that you have two faces fused at the leading/trailing edge. See the very simplified geometry attached. I've had meshing problems having only one face. |
OK, Linnemann was right. I partitioned the blade geometry and NETGEN mesh exporting (almost) works. In other words, I think that I experienced two bugs about boundary conditions editing. I use NETGEN 4.9.12 on Ubuntu 10.04 LTS.
1. Only one patch is highlighted when I select it in the Edit Boundary Conditions menu (the similar Edit Face Mesh Size works!). 2. I bypass the above bug noting the matching index number - face, so I can build boundary patches from solid faces. But when I export the mesh to OpenFOAM (in OpenFOAM 1.5+ or neutral format), the matching index-patch changes (only for two faces) - I checked it out by ParaView. Are these NETGEN or OpenFOAM troubles? How can I bypass the bugs (a different exporting format or other tricks)? I exported a NETGEN 2D- mesh in Gmsh2 format for enGrid and I created a 3D-mesh with a boundary layer (and conversion to OpenFOAM works), but I'd like to generate a 3D-mesh in NETGEN and export it to OpenFOAM without problems. |
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