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Mesh refinement for a cylindrical mesh

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Old   January 20, 2011, 06:54
Default Mesh refinement for a cylindrical mesh
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Hi Foamers,

although I have read a lot oft posts concerning this topic, I couldn't really find an answer. Therefore sorry if it maybe was already answered!

I have created the attached mesh using blockMesh:


What I now want to do is to refine a certain area at the corner of the mesh.
Earlier I had a cube where I could refine a specified area easily using the cellSet command, but in this case, the structure of my mesh gets lost. Is there a similar tool to refine certain areas which are not "box-shaped"?

Thanks!
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Old   February 4, 2011, 08:42
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little workaround is with cellSet and refineMesh with a local coordinate system. But I'm still interested in other suggestions about how to get around that cellSet only allows boxToCell, which is not optimal for the mentioned geometry.

Greetings
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Old   February 7, 2011, 17:55
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Quote:
Originally Posted by lindstroem View Post
little workaround is with cellSet and refineMesh with a local coordinate system. But I'm still interested in other suggestions about how to get around that cellSet only allows boxToCell, which is not optimal for the mentioned geometry.

Greetings

cellSet also has cylinderTocell option which can extract the cells in the cylinder regions specified
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Old   February 10, 2011, 09:31
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Hi thanks for the hint! Coudl you help me with the syntax? I havent found any use of it so far...

Thanks!
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Old   February 10, 2011, 14:16
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Usage: cylinderToCell (p1X p1Y p1Z) (p2X p2Y p2Z) radius
Select all cells with cell centre within bounding cylinder
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Old   July 30, 2012, 09:00
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hi lindstroem,

I tried cylinderToCell to generate cylinder but the boundary is not smooth (https://docs.google.com/drawings/d/1...DW5AXeEmY/edit)since I used blockMesh to set the domain, do you have any idea about how to set the region instead of blockMesh?

Regards,
T
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Old   July 30, 2012, 09:06
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Hi Teemo,

you want to "generate a cylinder"? some options are snappyHexMesh or O-Grids for cylinders (can be done with blockMesh). But I do not undersant your actual problem..

Greetings
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Old   July 30, 2012, 09:19
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Hi Lindstroem,

Sry for the bad description, I would like to test the wave load on the simplified floating cylinder-shape structure in a water tank, so I used one block to generate the whole tank and then employed toposet with cylinderToCell source to model the vertical floating object, while in paraview, you will see that the boundary of the cylinder is not smooth as as the mesh is made of only cuboidal cells(https://docs.google.com/drawings/d/1...DW5AXeEmY/edit).

Thanks,
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Old   July 30, 2012, 09:34
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Hi again,

Could you link me any tutorial of using snappyHexMesh or O-grids for cylinders?

Many Thanks!
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Old   July 30, 2012, 10:08
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I'm still not sure if I get you right, but the tutorial for snappy can be found by searching for snappyHexMeshDict in your tutorial folder (e.g. grep -r snappy .) and in the User Guide and for O-Grid see the forum:
Meshing a disc like this

But if you select your cells after creation I don't know how you could get rid of the staggered bubble.. if it is just the phase fraction, it will be "smooth" after the first iteration.

Greetings
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Old   July 30, 2012, 12:03
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Hi Lindstroem,

Sry for my bad English, it is not my first language.
The video linked below is what I would like to simulate.
http://www.youtube.com/watch?v=AuNWovYR6WA

My problem is :In my case, Firstly the wave tank are meshed by BlockMesh (just one block). Then I model the cylinder by using cylinderToCell but the cylinder boundary are not smooth since all cells created by blockMesh are cube.(https://docs.google.com/drawings/d/1...e6NzNv1hk/edit)
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Old   July 31, 2012, 04:24
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Yes, I would recommend snappyHexMesh (sHM) for that: So you use your inital block you created and within your sHMDict you define the cylinder you want to cut.. Then let sHM do the work for you and simulate your waves.

Greetings
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