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[ICEM] ICEM - Need suggestions on how to resolve blocking problem

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Old   January 2, 2015, 15:56
Default ICEM - Need suggestions on how to resolve blocking problem
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Hello all,

Long time lurker, first time poster. I have got a little problem on my hands that I have not been able to solve solo, and would appreciate suggestions.

I am having problems resolving the shape of my inlet, after blocking and Pre-meshing. I have attached a picture of my CV ('CV iso.jpg'). As you can see, the blue is a semi-circle inlet, yellow is my outlet, green is my wall, and the side you cannot see is my symmetry plane.

The attachment labeled 'Blk iso.jpg' gives you an understanding of my blocking configuration. I used and O-grid to resolve the curved surface of the structure. However, when I update and pre-mesh, I no longer get my semi-circle, and my inlet is now restricted to a quarter circle - as seen in 'PM iso.jpg' and 'PM inlet.jpg' (ignore the sloppy element configuration/refinement, I will rework that later).

Now that we are all on the same page, I want to state that I understand why ICEM is not generating my inlet as a semi-circle - i.e. there has only been an O-grid generated for part of the semi-circle, and ICEM cannot structure the remaining quarter circle without and O-grid. With that being said, when I try to use O-grid to complete the semi-circle, my CV essentially get destroyed (e.g. see 'PM fail.jpg')

I would like to know if anyone has any suggestions/references/tutorials on how to create a structured for the remaining quarter circle that is currently being occupied by the outlet BC, while retaining my CV shape and element quality.

Thank you for your time.
Attached Images
File Type: jpg CV iso.JPG (20.6 KB, 38 views)
File Type: jpg Blk iso.jpg (20.5 KB, 30 views)
File Type: jpg PM iso.jpg (53.8 KB, 31 views)
File Type: jpg PM inlet.jpg (29.9 KB, 39 views)
File Type: jpg PM fail.jpg (51.9 KB, 28 views)
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Old   January 3, 2015, 08:50
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Quote:
Originally Posted by NPGrad View Post
Hello all,

Long time lurker, first time poster. I have got a little problem on my hands that I have not been able to solve solo, and would appreciate suggestions.

I am having problems resolving the shape of my inlet, after blocking and Pre-meshing. I have attached a picture of my CV ('CV iso.jpg'). As you can see, the blue is a semi-circle inlet, yellow is my outlet, green is my wall, and the side you cannot see is my symmetry plane.

The attachment labeled 'Blk iso.jpg' gives you an understanding of my blocking configuration. I used and O-grid to resolve the curved surface of the structure. However, when I update and pre-mesh, I no longer get my semi-circle, and my inlet is now restricted to a quarter circle - as seen in 'PM iso.jpg' and 'PM inlet.jpg' (ignore the sloppy element configuration/refinement, I will rework that later).

Now that we are all on the same page, I want to state that I understand why ICEM is not generating my inlet as a semi-circle - i.e. there has only been an O-grid generated for part of the semi-circle, and ICEM cannot structure the remaining quarter circle without and O-grid. With that being said, when I try to use O-grid to complete the semi-circle, my CV essentially get destroyed (e.g. see 'PM fail.jpg')

I would like to know if anyone has any suggestions/references/tutorials on how to create a structured for the remaining quarter circle that is currently being occupied by the outlet BC, while retaining my CV shape and element quality.

Thank you for your time.
mesh>load from block
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Old   January 4, 2015, 19:13
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Hey ztep,

mesh> load mesh from blocking suggestion will not work, since my pre-mesh does not meet my requirements (i.e. bad load mesh in = bad load mesh out). My question is not how to create a mesh, but how to transform the existing mesh to incorporate the aforementioned missing quarter circle in the inlet boundary condition.
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Old   January 5, 2015, 14:46
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Hello all,

I was able to figure it out. It was simply how I dealt with my associations during the blocking phase of the mesh development.

For a majority of my blocking I used 'associated vertices'. I guess ICEM requires that you associate a curve and an edge in order for your boundaries to be clearly defined. I.e. every curve of your boundary must be associated with an edge.
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Old   January 5, 2015, 15:19
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It seems you have a singularity in your geometry (the small space between the top surface and the half-circle) and you will not be able to put a decent hex in it. Do you really need to keep the half-circle in its integrity ?
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Old   January 5, 2015, 15:44
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I see what you are saying, and I have some slight wiggle room? What geo modifications do you suggest?
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Old   January 5, 2015, 15:53
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It depends, if you need the whole half-circle or not.
- If not, just suppress the green blocks we see on the snap
- If yes, change it for a no-curved connection with the top surface.

Either way I would suppress those green blocks that should not be there ?
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File Type: jpg 2.jpg (27.9 KB, 21 views)
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