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[ANSYS Meshing] How to improve a simple mesh with a negative volume

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Old   May 31, 2012, 11:18
Default How to improve a simple mesh with a negative volume
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Hi there,




I was wondering what options i have on improving the mesh. I seem to be giving a negative volume. (4.3e-4).

This seems pretty large. Ive altered the mesh a number of times however this figure is still relativly low. Ive also tried creating the geometry from scratch but no luck.

I have tried mesh/repair-improve/repair and various others in the text command however do not get any change with the volume.


Please let me know what i can do to improve the mesh or sources to find out how todo this.


Thanks again for your help.
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Old   May 31, 2012, 12:08
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One way I do it, i start by a coarse mesh then i refine gradually. i often get them when i set a very small spacing in the edge parameter and i don't know why. I then go back to icem and set a bigger spacing. can we take a look at your mesh ?
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Old   May 31, 2012, 12:32
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Hi there,

Ive attached a copy of my mesh, also of a courser mesh which i also tried.

Although it was better (2.5e-3) this is stll pretty poor.

I may even need a finer mesh then the fine one attached to provide the end results i require.

Please let me know what i can do to improve it.

Thanks so much for your help.

By the way im using ANSYS meshing 13.0.
Attached Files
File Type: pdf Course mesh..pdf (38.3 KB, 21 views)
File Type: pdf fine mesh...pdf (86.8 KB, 24 views)
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Old   May 31, 2012, 12:36
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they look pretty good. would you mind sending the msh file. or the geometry file ?
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Old   May 31, 2012, 12:51
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Sure.

Here is the geometry file

If you send me your email i can send you the whole fine.

Im not sure how to send the .msh file.?
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File Type: zip Geom.zip (7.8 KB, 2 views)
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Old   May 31, 2012, 13:09
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it depends on which meshing tool did you use.i guess you're using ansys meshing, you can do that under file - export - msh file.
By negative volume you mean -2.5e-03, just to make sure
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Old   May 31, 2012, 13:19
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Hi Ali,

Please find the mesh file.

Yeah its 3.146130e-4.

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File Type: zip Mesh file.zip (36.2 KB, 2 views)
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Old   May 31, 2012, 13:58
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your mesh is fine as i suspected 3.14e-4 is not negative !! -3.14e-4 is negative.
Right ?!!
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Old   May 31, 2012, 14:06
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Is this figure acceptable?

I feel a litttle stupid now. Thought it had to be a higher Volume.

Thanks so much for your help
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Old   May 31, 2012, 14:09
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i think so. did you perform an analysis or not yet, depending on what your simulating you may need to refine your grid. but for now it's ok. get back to us with some results.
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Old   May 31, 2012, 14:13
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I did try but wasnt getting a solution. I thought it was because of the mesh.

Ill play around with the boundary conditions and see if i can work it out.

Thanks again
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