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Problem extruding Boundary Mesh

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Old   January 23, 2014, 18:09
Default Problem extruding Boundary Mesh
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Francisco Miguel
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Hello,

I don't know if there is something wrong with my geometry or if this is a bug in engrid, but I have been trying to create a mesh around a simple strut, and when I extrude the boundary layer some points do not get extruded and/or the boundary layer mesh shows "holes" in it. I think that this is causing NETGEN to crash if I try to continue with the process. Has anybody else experienced this problem? Is there an easy solution?

Thank you,

Francisco
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Old   January 24, 2014, 20:08
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Bruno Santos
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Greetings Francisco,

Can you share any images of the problematic locations? Because from the description you've given, I'm not managing to picture it in my mind

Best regards,
Bruno
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Old   January 24, 2014, 22:56
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Francisco Miguel
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These are a few pictures of the BL mesh and the surface below it. Thanks
Attached Images
File Type: png 1.png (27.8 KB, 32 views)
File Type: jpg 2.jpg (100.3 KB, 31 views)
File Type: jpg 3.jpg (38.2 KB, 30 views)
File Type: jpg 4.jpg (92.0 KB, 75 views)
File Type: jpg 5.jpg (77.7 KB, 24 views)
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Old   January 25, 2014, 09:42
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Hi Francisco,

The fourth image is showing some reasons of concern about the surface mesh. The triangles on the right are very thin and that darker part of the mesh, where it seems to sink into the volume, is a very big reason of concern.

A few questions:
  1. Is that darker region implying that there are some surfaces that are not being meshed?
  2. Are you keeping each curved and flat surfaces on their own boundary code, or are you leaving them together in a single item?
  3. When the boundary layer finished, does it give any warning or error messages?
Best regards,
Bruno
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Old   January 25, 2014, 10:26
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Francisco Miguel
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Hi Bruno,

The darker region is the part in which the BL mesh is not being extruded properly. It shows as a "hole" and that is why it looks darker. Right now, every surface on the strut has their own boundary code, with the leading edge separated into another so that it can be assigned a finer mesh. I have found that this also prevents the smoother to do funny things because of the change in curvature. No error messages appeared. I was having problems with overlapping faces, but those are solved now.

Thanks,

Francisco
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Old   January 25, 2014, 12:37
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Hi Francisco,

On that problem location, what does the original geometry look like?

Best regards,
Bruno
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Old   January 25, 2014, 13:03
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Francisco Miguel
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Hi,

This is how the blender import looks like. It is like this for the whole leading edge.

Thanks for the help,

Francisco
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File Type: jpg 6.jpg (39.2 KB, 18 views)
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Old   January 26, 2014, 07:03
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Hi Francisco,

Are you sure that is the right image/location? I was asking about the original geometry on the location for the 4th image, namely this one:


If it is the correct location, do you have at least 3 boundary codes for describing this region? On on the top, another on the bottom and another for the curved edge.

Best regards,
Bruno
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Old   January 26, 2014, 21:58
Default EnGrid crashes when creating boundary layer
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Richard
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[post deleted]
Attached Images
File Type: jpg Screenshot 2014-01-26.jpg (47.9 KB, 19 views)
Attached Files
File Type: zip sphere_140126.zip (80.2 KB, 4 views)

Last edited by pirsquared; January 27, 2014 at 00:23. Reason: Solved problem
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Old   March 23, 2014, 05:07
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Quote:
Originally Posted by pirsquared View Post
[post deleted]
Hi Richard,
Prism layers generated without any problem. See the file showing the boundary layer mesh over the sphere.
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File Type: jpg sphere_bl.jpg (40.4 KB, 25 views)
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