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[ICEM] Uncovered edges on Fluent mesh

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Old   May 8, 2013, 08:16
Default Uncovered edges on Fluent mesh
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Augusto Fontan
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Good morning,

I'm trying to create a 2D mesh for a scramjet intake to be used in Fluent. In order to simulate the viscous flow, we need to condense the mesh along the walls, so I had to divide the geometry in multiple blocks in order to condense where needed, as seen in the figures, along with the pre-mesh with focus on where I need it condensed.

The issue is, whenever I try to export it as a .msh file for Fluent, it tells me I have uncovered edges. I have tried rebuilding the geometry edges in ICEM from the points coordinates, but to no success.

Maybe it has to do with the interior edges I have created to separate the blocks? I'm out of ideas as to what to do.

Thanks in advance for any help.
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File Type: jpg blocks.jpg (10.8 KB, 19 views)
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Old   May 8, 2013, 09:30
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It is the association problem. Check all your boundary edges are green.
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Old   May 8, 2013, 09:33
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Far, thanks for the reply.

I've checked and all the edges are green. I've been careful furing association in order to avoid any issues specially at the wedges.
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Old   May 8, 2013, 09:34
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Attach files... let me check them
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Old   May 8, 2013, 09:51
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Files are too big for the forum, I've uploaded them HERE.

I can also send them directly to your email if you prefer. If there are any files missing, please let me know.

Thanks again for the help.
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Old   May 8, 2013, 11:50
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Hi Fontan,

How did you do the geometry? I think the problem is the geometry. Ive tried to do the mesh too and I got the same problem. Then Ive tried "Build Diagnostic Topology" because Ive seen some weird connections and if you click in "Delete unattached curves and points" all the curves dissapears. So.. how did you do it?
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Old   May 8, 2013, 12:04
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Thanks for the reply, Javi.

I did it using AutoCAD 2013 and exported as an .iges file.

I suspected the geometry to be the issue and tried deleting the edges and reconstructing it entirely in ICEM using the intersecting points, but it didn't work as well.
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Old   May 8, 2013, 12:23
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Ok. Problem was solved with merge vertices operation. You have disconnected blocks and issue resolved with merging vertices.

Another issue was association of blocks edges with internal edges, this should be avoided. Only associate perimeter edges where boundary is defined.

Also there were no points, so also made them and vertices were associated with respective point, again be careful in over-associating vertices.

Files are attached and you can specify spacing as deemed necessary.
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File Type: zip scramjet_Far.zip (9.1 KB, 15 views)
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Old   May 8, 2013, 12:51
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Hi Far,

I dont understand you when said "you have disconnected blocks". Is it possible? And... when you solve this issue.. you use "merge vertices"... but.. what are those vertices?

About points. I created the points and then associated them with vertices. I think is better in that way. But, are they necessary in this case?
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Old   May 8, 2013, 14:09
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please refer to following pics ...



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Old   May 8, 2013, 15:33
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Thank for the explanation Far.When I saw the blocking strategy it seemed a bit weird. In fact, I merged the blocks (exactly where you write "no need" in purple). And.. whats about points? Are they necessary?
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Old   May 8, 2013, 15:37
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Actually it was by default in my mind that outermost vertices should be associated to points as explained in ICEM tutorials (static mixer and sphere cube).

Quote:
blocking strategy it seemed a bit weird
Overall blocking strategy is perfect. But when he made split horizontally (making three blocks), he deleted blocks which are not being used but forgot to merge vertices in the interior of intake.

Better approach would have been to collapse blocks in that region, thus avoiding the need of merging vertices. Just think if there were 100's of parallel blocks with same problem, it would have been cumbersome to manually merge each vertex pair.
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Old   May 8, 2013, 15:45
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Far, thank you very much. I'm heading home right now, but I'll check it out as soon as I get there.

Thank you as well for the explanation regarding the merging of the vertices, I'll be sure to keep that in mind in the future.
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Old   May 8, 2013, 15:49
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Thank you again for you advise!
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