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[ANSYS Meshing] Trouble with convergence

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Old   August 25, 2014, 09:39
Default Trouble with convergence
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Hi all,

I am having trouble with converging one of my 2D simulations.
I have attached an image of the geometry and my mesh.
The mesh is very good quality >0.7 and min angle > 18 degrees.

However, when I run it for simple laminar flow, there appears to be a large pressure building up at the corner (see image 'Close Up') and this prevents the system from converging.

Does anyone have any meshing tips on how to improve this mesh so that simulation converges?

Thanks,
Andreas
Attached Images
File Type: jpg quality.jpg (99.0 KB, 13 views)
File Type: jpg block.jpg (68.2 KB, 16 views)
File Type: jpg stenosis.jpg (94.4 KB, 12 views)
File Type: jpg close_up.jpg (100.2 KB, 14 views)
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Old   August 25, 2014, 11:50
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Hi Andreas,

i would suggest to try to match the element sizes of adjecent blocks. The expansion ratio could be too high.
Have look at the corner at the smallest element in screen 4. On top of the left block, elements seem to be more than 6 times as big as adjacent elements. In sense of numerics, that's a problem. Often it's recommended to maintain an expansion ratio of 1.2 or smaller.

With regards,
Sebastian
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Old   August 25, 2014, 12:21
Default Blocking is not good
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Try some better blocking


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Old   August 27, 2014, 11:45
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Hi Bluebase and Far,

Thank you very much for your tips. I will give it another shot.

Regards,
Andreas
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