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-   -   [GAMBIT] Surface Meshing Issues in Gambit (http://www.cfd-online.com/Forums/ansys-meshing/63043-surface-meshing-issues-gambit.html)

Forrest March 26, 2009 12:04

Surface Meshing Issues in Gambit
 
I have a pipe with a square hole (cut out of the pipes side) that I would like to mesh in Gambit. I have simplified the problem by using the symmetry of the domain. I have three volumes that will eventually be meshed: (1) the interior volume of the pipe, (2) the volume of the hole, and (3) the volume around the pipe. I have already successfully meshed the volume of the hole in the pipe as seen in Image 1 (the orange mesh in the photos). I am trying to mesh the shaded face in Image 2. I want to use hexahedral elements with the map scheme on this face, but Gambit says that the face is not a mapable region and uses the submap scheme to generate the mesh shown in Image 3. I want a nice non-skewed mesh because I'm going to use the Cooper scheme to mesh the outer volume. Is it the inner mesh that messing up my face mesh? Is there anyway that I can fix this or is there a better approach to meshing my domain than splitting it into three volumes and meshing each one separately? Thanks in advance!

http://lh6.ggpht.com/_-cnbldNBBl4/Sc...cture%2011.png

http://lh6.ggpht.com/_-cnbldNBBl4/Sc...cture%2010.png

http://lh4.ggpht.com/_-cnbldNBBl4/Sc...cture%2012.png

-mAx- March 26, 2009 14:49

decompose the shaded surface in 2 surfaces (with revolution around the axis).
One surface will be beyond the orange mesh
One surface will be below the orange surface
The last surface will be the "projection" of the orange mesh.
I hope you will understand :rolleyes:
Anyway the you should be able ton have 3 nice mappable surface meshes

Forrest March 26, 2009 15:57

Ok, I was able to split the surface (using the split surface command with virtual edges). After trying to mesh these new faces, I found that I need to modify my edge meshes so that they have even numbers of intervals. I didn't do anything with the orange mesh since I assume that Gambit will connect the outer volume mesh with the orange one. Was the way I did it what you had in mind MAX?

-mAx- March 27, 2009 01:53

hmm... did you already created the edges for splitting? because on the pictures I didn't see any edges for the split I mean.
On the second picture I only see the possibility to split the surface with vertices (On the left side , it seems to be 3 vertices which are symetric to the one on your orange mesh).
If you see what I mean, try to split the shadded surface with a pair of two opposite vertices. I will generates a semi-circle. If it's ok, do the same for creating the 2 next curves.

Forrest March 27, 2009 15:22

Thanks max! What you suggested worked great. I was able to split the original shaded region into three new faces and after some finagling I was able to mesh it using quad/map (as you can see below). I had to remove the orange volume mesh to get the edge mesh back for gambit to be happy, but it went back together nicely. Thanks again.

http://lh4.ggpht.com/_-cnbldNBBl4/Sc...cture%2015.png


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