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[Star-CCM+ v9] Dynamic Overset Mesh basic problem

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Old   June 5, 2014, 11:41
Default [Star-CCM+ v9] Dynamic Overset Mesh basic problem
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Cyril Gomez
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Hi all,

I come back to you again after my previous topic on successive rotations. Somebody perfectly answered me so i was very happy, but now i got another problem ; much simpler however

I want to overlap 2 overset meshes. I had always been told it was impossible, but i have also heard recently that it's possible in version 9 (it is also written in Help under Dynamic overset section)

So i have tried to overlap two overset boundaries from 2 different regions. i get the following error :

" Error in surface mesh of Region [Overset 1 ; Overset 2] : Surface is self intersecting." I precise that i have done all that was written in documentation (creating additional interface between the two overset regions, among other things)

I have tried dynamic overset meshing (that is to say, setting all overset boundaries to wall boundaries and enable dynamic overset) but i still get the same error.
As often with star-CCM, the problem is simple to solve, i think it's just a little thing i don't know that i didn't do, and i don't find in help or documentation...

Please help me <3
johncoffey

Last edited by johncoffey; June 6, 2014 at 03:48.
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Old   June 6, 2014, 16:17
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This isn't a problem with overset, this is a meshing problem.

Ensure that you have per-part or per-region meshing enabled for overset meshing.

You should be able to launch surface repair on your remeshed surface to identify the source of the intersecting faces.
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Old   June 10, 2014, 03:57
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Cyril Gomez
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I forgot to specify that my problem was occuring when i generated mesh.

You were totally right : I enabled "Per-Region Meshing" in my continuum mesh, and it works now !!

Thanks a lot me3840, once again you helped me accurately ^^ even if it was just a tick i would never have found it alone before 3 months hehe.

I am now trying to overlap the overset region of the first body with the wall region of the second body (i saw it was possible in the documentation)

Hoping this post will help for other people to overlap overset meshes.

johncoffey
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Old   June 17, 2014, 12:44
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Cyril Gomez
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Hello again,

I'm coming back to the dynamic overset meshing because I'm encountering a mistake in my simulation.

I'm using dynamic overset meshing without background in starCCM+ v9, with two overset meshes whose boundaries overlap each other. The overset boundaries are cubic and surronding simple spheres.

I have read the documentation (see attached picture) which says that two overset boundaries can overlap if we set dynamic overset, which consists in setting them to wall boundaries and enabling dynamic behaviour.

When i do that, i don't encounter any error on meshing nor initialization. But what happens, is that there are ACTUALLY cubic walls around my spheres ; and no walls where boundaries overlap.
So i think that just like on the picture, the boundaries ARE walls where the boundaries don't overlap, and are overset where they overlap.
But i don't want walls surrounding my spheres !

Please can you tell me how can i have overset boundaries all around my spheres without background? Because when i follow the procedure in the documentation (wall boundary + tick dynamic behaviour) it doesn't work

If you have any question tell me,
Thanks a lot,
johncoffey
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File Type: gif dynamicOversetBehaviorExample_annotated.gif (32.1 KB, 94 views)
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Old   June 17, 2014, 13:12
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I'm confused. You want the outermost boundaries to not be walls, but also to not be overset with anything? What is the BC you want to use?
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Old   June 17, 2014, 14:14
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I want my cubic domains around my sphere to be overset mesh boundaries, and my spheres to be wall boundaries.

I just set wall boundaries for the cubes because it's the procedure written in the documentation, and if i let overset mesh as BC, then it doesn't work, i get an error
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