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March 26, 2024, 11:43 |
Bad quality mesh
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#1 |
New Member
Join Date: Mar 2024
Posts: 3
Rep Power: 2 |
Hi,
I am doing a CFD wind tunnel test for a front wing geometry on Ansys fluent meshing for my final year project. I have been trying to get the minimum orthogonality to be 0.1 or above but can't seem to be able to increase it much above 0.01. This problem occurred when inflation layer was added. Inflation Layer conditions:
Other conditions:
Any help will be much appreciated. Thank you |
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March 27, 2024, 01:58 |
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#2 |
Senior Member
Stuart
Join Date: Jul 2009
Location: Portsmouth, England
Posts: 735
Rep Power: 25 |
Most likely that the aspect ratio of the elements is too high. Presumably, you've calculated that first layer height based on a required y-plus value.
As a test, change to Smooth Transition for 5 layers (defaults). Is that OK? If you now increase the number of layers (without changing anything else) how does the element quality drop? Watch these: https://courses.ansys.com/index.php/...undary-layers/ |
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March 27, 2024, 10:52 |
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#3 | |
New Member
Join Date: Mar 2024
Posts: 3
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Quote:
Number of layers, Min Orthogonality 5, 0.1615 7, 0.1064 10, 0.0963 13, 0.0638 15, 0.0278 17, 0.0383 20, 0.0096 Thank you Last edited by Donald_Wu; March 27, 2024 at 19:25. |
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March 28, 2024, 03:26 |
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#4 |
Senior Member
Stuart
Join Date: Jul 2009
Location: Portsmouth, England
Posts: 735
Rep Power: 25 |
Did you try the Smooth Transition method?
However, my guess would be that with the lowest height first layers (thus highest aspect ratio) then a slight distortion of the high aspect ratio adversely affects the minimum orthogonal quantity. Then then only way to reduce the aspect ratio of the first element is to decrease the surface element size on the regions of concern. Can you put a local face sizing (maybe you need to split the face in SpaceClaim and put in in a Names Selection aka Group in SpaceClaim, and see how that affects the quality metric. |
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March 28, 2024, 23:29 |
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#5 | |
New Member
Join Date: Mar 2024
Posts: 3
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Quote:
I tried decreasing the surface mesh size at the affected region and the orthogonality increased. Thanks for helping! |
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