# [GAMBIT] Cannot mesh with cooper scheme

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April 28, 2013, 14:29
Cannot mesh with cooper scheme
#1
Senior Member

Daniele
Join Date: Oct 2010
Location: Italy
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Hi!
I have to mesh the domain you can see in the attached pictures, with full hexa.
It id a "double helical coil" immersed in an aluminum block".
The domain is composed by 4 volumes.
I successfully meshed faces and I wanted to mesh the each volume with the cooper scheme, but gambit returns:

"Volume cannot be meshed because two sets of source faces which form natural starts for the projections could not be found."

I don't understand, in my opinion the 2 sources are of (bottom and top)..
What's wrong?

Thank you,

Daniele
Attached Images
 immagine1.jpg (91.8 KB, 24 views) imamgine2.jpg (95.5 KB, 16 views) immagine3.jpg (99.4 KB, 18 views) immagine4.jpg (79.7 KB, 15 views)

 April 29, 2013, 01:37 #2 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,145 Rep Power: 32 try to split the volume along (yz) Instead of 180° rotation volume, you will have 2x 90° (it may help). __________________ In memory of my friend Hervé: CFD engineer & freerider

April 29, 2013, 03:30
#3
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Daniele
Join Date: Oct 2010
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Quote:
 Originally Posted by -mAx- try to split the volume along (yz) Instead of 180° rotation volume, you will have 2x 90° (it may help).
I managed to split each of the 4 volumes into different volumes by projecting the spiral edges on the top/bottom surfaces and mesh them with hex submap.
I think of meshing the central zone of the domain with map, but I have too coarse regions in that zone, so the only solution I find is to split each of these zones into "3" volumes, assign fluid names and refine them directly into fluent: do you think is it acceptable (see sketch in the picture)?.

Thank you,

Daniele
Attached Images
 immagine.png (44.2 KB, 20 views)

 April 29, 2013, 03:55 #4 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,145 Rep Power: 32 -Are you now able to mesh the volumes, which gave you problem? -can you refine non-tetrahedral zones in fluent? __________________ In memory of my friend Hervé: CFD engineer & freerider

April 29, 2013, 03:59
#5
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Daniele
Join Date: Oct 2010
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Quote:
 Originally Posted by -mAx- -Are you now able to mesh the volumes, which gave you problem?
Yes, now problem is solved; all volumes are meshed with hexa; my doubts are about the central zone(s).

Quote:
 -can you refine non-tetrahedral zones in fluent?
I think so, I never tried, but in the past I was able to refine 2d quadrilateral cells, I have to try..

Thanks,

Daniele

May 1, 2013, 09:23
#6
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Daniele
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Dear all, dear Max,
my idea does not work very well...
For completeness I can say that fluent let you refine hexa mesh (see attach image): the cube is splitted into 8 regions and refined different times; when refining 2 times fluent automatically adds refining to adjacent zones, in other word you can have adjacent cells (edges) smaller/greater than 50%/200%.

As I wrote I was successfully in meshing "peripheral volumes" with hexa, but my problem remains at the center of the spiral; any comments on splitting the central volume is welcome.

Daniele
Attached Images
 Catturaimg.PNG (41.4 KB, 14 views) Cattura333.jpg (90.6 KB, 16 views) Cattura222.jpg (98.0 KB, 11 views) Cattura111.jpg (97.2 KB, 12 views)

 May 2, 2013, 02:05 #7 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,145 Rep Power: 32 Hello Daniele, Once you are sure that your "already meshed volumes" are hexa-meshable, I would delete those mesh, and I would start meshing the center of the spiral. If you don't have any meshed volume, then you are "free" with hexa-start-meshing. Once the center of spiral is meshed, you won't have any problem to mesh the rest (but I think you already know that). Regarding decomposition, maybe you could post a picture with only the center of the spiral (shaded mode on), to see more details. __________________ In memory of my friend Hervé: CFD engineer & freerider

May 2, 2013, 02:48
#8
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Daniele
Join Date: Oct 2010
Location: Italy
Posts: 992
Rep Power: 16
Quote:
 Originally Posted by -mAx- Hello Daniele, Once you are sure that your "already meshed volumes" are hexa-meshable, I would delete those mesh, and I would start meshing the center of the spiral. If you don't have any meshed volume, then you are "free" with hexa-start-meshing. Once the center of spiral is meshed, you won't have any problem to mesh the rest (but I think you already know that). Regarding decomposition, maybe you could post a picture with only the center of the spiral (shaded mode on), to see more details.
Thank you Max,
I'm attaching directly the dbs file, with part of geometry (center + adjacent volume): volumes to be problematic for me are volume 49 and 63.

Here the dbs:
http://www45.zippyshare.com/v/47192229/file.html

Thank you,

Daniele

 May 2, 2013, 09:37 #9 Super Moderator     Maxime Perelli Join Date: Mar 2009 Location: Switzerland Posts: 3,145 Rep Power: 32 Hello Daniele, I don't have time enough to really test and mesh your geometry, but did you try such a decomposition? The "Y" could be more reproduced, if your mesh get coarser. For volumes 49 & 63, you will have to split them with plane parallel at (xz) with y-offset 10.334201 (you already have some points at this level) Sans titre.png __________________ In memory of my friend Hervé: CFD engineer & freerider

May 2, 2013, 09:57
#10
Senior Member

Daniele
Join Date: Oct 2010
Location: Italy
Posts: 992
Rep Power: 16
Quote:
 Originally Posted by -mAx- Hello Daniele, I don't have time enough to really test and mesh your geometry, but did you try such a decomposition? The "Y" could be more reproduced, if your mesh get coarser. For volumes 49 & 63, you will have to split them with plane parallel at (xz) with y-offset 10.334201 (you already have some points at this level) Attachment 21398
Thank you Max for your input, I'm working on it.

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