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[ICEM] Low quality mesh

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Old   May 21, 2012, 11:59
Default Low quality mesh
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I have to mesh an object and some of its changes. The critical area is represented by two surfaces with an angle of 30 degrees.
After this process I have to import the mesh in fluent.

Until the creation of prism, the quality of the mesh appears very good (> 0.1-0.2).

I explain what I do step by step.

I import a acis format, built topology (all lines are red).
I create a Octree mesh, delete all the volume elements and proceed with a smoothing operation:
- 50 iterations up to 0.6 (Laplace with allow node merging activeted);
- 10 iterations up to 0.4 (no Laplace).

After I create a Delaunay mesh to fill the volume.

Before generating prism:
- 10 iterations up to 0.6 (Laplace);
- 10 iterations up to 0.6 (no Laplace);
- 10 iterations up to 0.6 (Laplace);
- 10 iterations up to 0.6 (no Laplace).


I extracted a good mesh with these prism settings, but I have to improve it:
Initial height: 0.0002 (this size is necessary).
Height ratio: 1.2.
Number of layers: 5.
Fix marching not activated.
Min prism quality: 0.01.
Ortho weight: 0.2.
Fillet ratio: 0.1.
Max prism angle: 180.
Smoothing options:
Surface smoothing steps: 0.
Volume smoothing steps: 10.
Max directional smoothing steps: 5.
First layer smoothing steps: 1.
Auto reduction activated.
Use existing quad layers.

I noticed that there are a lots of problematic tetra_4 elements that not disapperead after a smoothing.
Also often after the smoothing, the export fails.

I've try also different settings to limit the pyramids, but I didn't got good results:
Prism settings:
Exponential.
Initial height: 0.0002.
Height ratio: 1.2.
Number of layers: 5.
Fix marching not activated.
Min prism quality: 0.000001.
Ortho weight: 0.2.
Fillet ratio: 0.1.
Max prism angle: 180.
Smoothing options:
Surface smoothing steps: 0.
Volume smoothing steps: 10.
Max directional smoothing steps: 5.
First layer smoothing steps: 1.
Auto reduction activated.

Finally:
- 50 iterations up to 0.6, penta_6 freeze (no Laplace).
- 5 iteration up to 0.01 (no Laplace).

I do not know what to improve.
I used also thin cuts and edge criterion options.
Before the prism, the histogram appears clear until 0.2.
Thanks in advance and sorry for my english.
Best regards.
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Old   May 25, 2012, 02:02
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