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[ICEM] How to Coarsen Mesh in Selected Block

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Old   January 24, 2021, 17:09
Question How to Coarsen Mesh in Selected Block
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Hello Everyone,

I am trying to coarsen the mesh in a selected block. The ICEM manual tells me I can:
Use Blocking > Pre-Mesh Params > Refinement to refine or coarsen the mesh. You can apply the refinement/coarsening in all three major directions simultaneously or in just one major direction.
Refinement
To refine the mesh, enter a scale factor greater than 1.
Coarsening
To coarsen the mesh, enter a scale
factor less than 1.

I go to the refinement option and enter a scale factor less than 1 (see screenshot where I used 0.5), but it gives me an error and tells me that the factor must be positive.

Am I missing something? Thanks in advance
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File Type: png refinement.PNG (40.4 KB, 19 views)
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Old   January 24, 2021, 17:15
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I have found a solution.

I input 1/2 rather than 0.5 and it worked.

Edit: it seems to not like when I use a factor of 1/3 and gives me warnings as attached. What do they mean?

I am able to use 3X refinement in the opposite direction.
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File Type: png refinement_warning.PNG (18.7 KB, 12 views)

Last edited by aero_head; January 24, 2021 at 17:32. Reason: ran into another problem
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Old   January 25, 2021, 06:59
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That is just warning to hanging elements. Refinement "1/2" is for Fluent mesh. An "1/3" refinement is for CFX mesh. Look in Help on subsequent command "Edit Mesh > Merge Nodes > Merge Meshes".
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Old   January 25, 2021, 12:13
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Hello Ludvik,

Thanks for your reply.

I do intend to use the mesh in CFX. When I go through with the 1/3 refinement, the program actually closes on me, saying there is a segmentation violation. Would this still be due to the hanging nodes?
If I use 'Resolve Refinements', would that warning not appear?
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Old   January 26, 2021, 02:45
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The mesh refinement in Blocking really produce uncorrect mesh for CFX.
Switch Premesh to Unstructured Mesh and use tool "Merge Mesh, Method: Resolve Refinements" to solve this.
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Old   January 26, 2021, 22:19
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Hello,

Could you please describe what you meant when you said the mesh it would produce would be incorrect?
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Old   January 27, 2021, 05:04
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Word "incorrect" isn't exact, better is "impractical". In a model are too many Mesh Interfaces, who consumes time for creating model, computational time, .. .
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Old   January 27, 2021, 10:41
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Hello Ludvik,

Thank you for the additional information/clarification
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coarsen grid, icem, mesh, refinement

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