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[ICEM] Problems with mesh for annular-type geometry

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Old   March 19, 2012, 11:17
Default Problems with mesh for annular-type geometry
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Hello,

I'm new to ICEM CFD and I have encountered some problems I hope someone can help me with.

I'm trying to mesh the cylinder/annulus shown in the attached picture. It has an annular region at one end, but the inner cylinder doesn't extend to the opposite end of the outer cylinder. Also, the inner cylinder has a "cap" region with zero-wall thickness (I'm hoping it will be sufficient to prescribe a wall boundary condition for the simulations, as applying a wall thickness resulted in a skewed mesh with cells extending into the no-mesh zone).

My approach has been:
  • Create an initial block around FLUID and then split it at the end of the inner cylinder; associate edges to curves; make the end vertices periodic.
  • Create the first O-Grid for the inner cylinder so that I can then assign that part to SOLID and avoid meshing it.
  • Create a second O-Grid for the large cylinder and associate edges.
  • I then modify the edge parameters to refine the mesh along the walls.
When I check the mesh quality however, the cells at the interface between the two sets of blocks are not good. I tried to merge the side blocks to improve this (I don't want the inner part of the small cylinder to be meshed, so didn't merge the central blocks). Merging the side blocks results in another problem however: the node count on the merged edges no longer matches the node count on the inner edges of the blocks.

Am I going about blocking this geometry all the wrong way? Is there a way to improve the cell quality at the interface of the split?

I hope this post makes sense and that the attached images help.

Thank you in advance for your help,

Kristin

Model.jpg

Problem.jpg
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Old   March 19, 2012, 11:20
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A couple more images

Merge_Block.jpg

Merged_edges.jpg
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Old   March 19, 2012, 11:21
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Last two, I hope they clarify what I tried to describe in my post

Unmerged_Edges_1.jpg

Unmerged_Edges_2.jpg
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Old   March 19, 2012, 11:31
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whats the problem exactly, the procedure you have adopted seems to be ok . Attach blk and tin
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Old   March 19, 2012, 12:21
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Thank you for your quick reply Far.

I have attached the blk and tin files to an email sent to you on turboenginner@gmail.com.

The problem is that, due to the node count not matching in the axial direction following the merge of the blocks, a section view of the mesh looks like the image attached.


I look forward to helpful advice,

Kristin

Section_view.jpg

Last edited by Kristin_N; March 19, 2012 at 12:42. Reason: Mistake
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Old   March 20, 2012, 15:28
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Done. I shall upload video on youtube.

Some working on geometry was necessary as it helps to control the blocking.

Attaching tin and blk files.










Last edited by Far; March 21, 2012 at 00:26. Reason: Removed tin and blk files, as these were sent to me privatly
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Old   March 20, 2012, 15:40
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Similar problem is also discussed here.
Boundary condition is lost when export to Fluent .
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Old   March 21, 2012, 00:29
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Quote:
The problem is that, due to the node count not matching in the axial direction following the merge of the blocks, a section view of the mesh looks like the image attached.
This problem can be solved with linked bunching, if every thing else is ok.
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Old   March 27, 2012, 00:48
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Detailed procedure is given here.

Large and small cylinder with inner wall
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Old   March 28, 2012, 17:50
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Far,

Thank you very much for all your help, my mesh finally works!

Kindest regards,

Kristin
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