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[ICEM] Meshing a Bifurcation using Hexa

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Old   May 7, 2014, 13:37
Default Meshing a Bifurcation using Hexa
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Daniel
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Hello to all

I am trying to mesh a bifurcation geometry. I have managed to generate an unstructured mesh using Tetra/Mixed method.
However I am wondering if it possible to get a mesh like this one in ICEM using usual blocking?




Thanks in advance

D. Khazaei
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Old   May 7, 2014, 13:56
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Check out Simon's Tipps and Tricks documentation. It has a detailed description for blocking a very similar geometry (fork).
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Old   May 7, 2014, 14:02
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Quote:
Originally Posted by kad View Post
Check out Simon's Tipps and Tricks documentation. It has a detailed description for blocking a very similar geometry (fork).
Would please provide the link?

Best wishes
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Old   May 7, 2014, 14:07
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Hi Daniel,

I wondered the same thing few months ago, and as Kad said, simon'tips has two approaches.

Here the link (see 85 & 86 slides)

Simon's tip
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Old   May 7, 2014, 14:13
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Quote:
Originally Posted by FJSJ View Post
Hi Daniel,

I wondered the same thing few months ago, and as Kad said, simon'tips has two approaches.

Here the link (see 85 & 86 slides)

Simon's tip
Thank you both for your suggestions.

I will read this PDF and come back.
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Old   May 7, 2014, 15:11
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I don't think that blocking produce high quality mesh for circular tube at bifurcation region.
This is how I want the mesh look like:

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Old   May 7, 2014, 21:15
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I have tried to do the blocking as Simon suggested in his tips and tricks.

However, I don't know how to fix it:

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Old   May 8, 2014, 06:14
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Hi Daniel,

I´ve tried with a geometry similar to yours. The problem was the same, just the junction surface. Please, can you share your geom?
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Old   May 8, 2014, 08:10
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Quote:
Originally Posted by FJSJ View Post
Hi Daniel,

I´ve tried with a geometry similar to yours. The problem was the same, just the junction surface. Please, can you share your geom?
Of course...

Were you able to fix your problem?

Best wishes
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Old   May 8, 2014, 09:15
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Quote:
Originally Posted by FJSJ View Post

Please, can you share your geom (and blocking)?
Looks like a problem with associations. Check vertex and edge association. If these are correct associate faces manually to their corresponding surfaces.
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Old   May 8, 2014, 09:22
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Quote:
Originally Posted by kad View Post
Looks like a problem with associations. Check vertex and edge association. If these are correct associate faces manually to their corresponding surfaces.
I have tried to manually associate faces to corresponding surfaces, but the problem is still there.
However, about vertex and edge association:

It is a CAD geometry and there are to many curves there.

Do you think that the sharp angle in my blocking strategy is responsible for this problem?
Attached Images
File Type: jpg blocking.JPG (38.1 KB, 39 views)
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Old   May 8, 2014, 09:44
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The sharp angle could be a minor problem, but in general blocking should be doable. Your blocking looks not 100% okay in your last attachment. It looks like there are degenerated blocks near the sharp angle. But this could also be a matter of perspective.

Why don't you share your project? Would be much easier.
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Old   May 8, 2014, 09:55
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Quote:
Originally Posted by kad View Post
The sharp angle could be a minor problem, but in general blocking should be doable. Your blocking looks not 100% okay in your last attachment. It looks like there are degenerated blocks near the sharp angle. But this could also be a matter of perspective.

Why don't you share your project? Would be much easier.
I am trying to attach it here but the size is larger than the limit.
Now I am uploading the project on a another host.
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Old   May 8, 2014, 10:01
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Quote:
Originally Posted by kad View Post
The sharp angle could be a minor problem, but in general blocking should be doable. Your blocking looks not 100% okay in your last attachment. It looks like there are degenerated blocks near the sharp angle. But this could also be a matter of perspective.

Why don't you share your project? Would be much easier.
here is the full project:

Code:
http://www.rodfile.com/r86znlonj5zq

Last edited by Daniel_Khazaei; May 8, 2014 at 15:29.
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Old   May 8, 2014, 12:22
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What is the password?
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Old   May 8, 2014, 14:19
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After having a look at your project I must admit that our suggested blocking strategy is probably wrong. You can do it, but you will end up with some bad elements and run into trouble with ogrid creation (see att which is without ogrids).

Meanwhile I think I have understood the strategy in your posted pics. I will explain this later/tomorrow as I am going home now.
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Old   May 8, 2014, 15:44
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Quote:
Originally Posted by kad View Post
After having a look at your project I must admit that our suggested blocking strategy is probably wrong. You can do it, but you will end up with some bad elements and run into trouble with ogrid creation (see att which is without ogrids).

Meanwhile I think I have understood the strategy in your posted pics. I will explain this later/tomorrow as I am going home now.
Thank you very much.
I am eagerly waiting to hear from you.
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Old   May 9, 2014, 09:44
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I have attached the generic blocking structure for your geometry. Now you have to apply to your geometry. If possible I would strongly suggest a geometry clean up in CAD. I tried it myself in Designmodeler. It somehow worked but destroyed the surface structure.

If blocking is to hard you can also try ANSYS Workbench CutCell meshing. I just started to work with it this week and it gave decent results in a short time. It is really not hard to handle if you are familiar with other meshing tools.
Attached Images
File Type: jpg basic_structure1.jpg (9.5 KB, 66 views)
File Type: jpg basic_structure2.jpg (9.1 KB, 62 views)
File Type: jpg basic_structure3.jpg (11.2 KB, 61 views)
File Type: jpg ogrid_selection.jpg (19.4 KB, 80 views)
File Type: jpg final_structure.jpg (23.0 KB, 62 views)
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Old   May 9, 2014, 09:47
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Blocking attached. The .blk* (e.g. .blk3) show the progress of work.
Attached Files
File Type: zip dk_tutorial.zip (26.4 KB, 32 views)
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Old   May 9, 2014, 09:56
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Quote:
Originally Posted by kad View Post
I have attached the generic blocking structure for your geometry. Now you have to apply to your geometry. If possible I would strongly suggest a geometry clean up in CAD. I tried it myself in Designmodeler. It somehow worked but destroyed the surface structure.

If blocking is to hard you can also try ANSYS Workbench CutCell meshing. I just started to work with it this week and it gave decent results in a short time. It is really not hard to handle if you are familiar with other meshing tools.
Quote:
Originally Posted by kad View Post
Blocking attached. The .blk* (e.g. .blk3) show the progress of work.
Thank you very much for the help man.

I will try to work this out.
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