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[Other] mesh generation for porous media

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Old   April 11, 2016, 08:51
Default mesh generation for porous media
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Manu Chakkingal
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Hai

I would like to generate mesh for random distributes of small sphere inside a cylinder (which in turn result in a porous media). I would like to know how can I approach it for geometry creation

i.e how to get a distribution of spheres inside the geometry (cylinder).

And how to do the meshing.

Could anyone suggest any tutorial for the same
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Old   April 26, 2016, 06:45
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Hi,

I do not know what you actually want to do but if I got the point correct you will mesh a cylinder and inside there are small sphere's that at last act as a porous media.

So for the inner sphere's you should make a CAD model, and you have to define the diameter and the distribution. After that you can mesh the stuff using snappyHexMesh or even better. If you know the properties of the porous media, just use a porous zone for modelling the flow.
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Old   April 26, 2016, 06:50
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Hi Tobias

Thanks for the reply. I would like to a structured mesh around the arrangement of spheres.Does snappyhexmesh serve the purpose (I think it would create tetra elements at the intersection of spheres). My intended geometry is as below
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Old   April 26, 2016, 06:53
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If the sphere's will meet at one point, you will always have problems in meshing. Either you put them a bit away or you make a simplification that the connecting point is replaced with some small tube or sth. like that. Meshing that with blockMesh (good luck). SnappyHexMesh is doing hex-dominant meshing but you can have hex-cells as layers around your spheres. But you should make some simplifications to your spheres. I would prefer the second one.
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Old   April 26, 2016, 07:38
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Ok. I get your 1 suggestion perfectly..but vcould you please share some info/thread on "simplifications to your spheres" to use snappyhexmesh to obtain structured mesh.
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Old   April 26, 2016, 09:26
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Hi,

snappyHexMesh will always return a hybrid mesh (hex-dominant) due to the fact how it works. Anyway I would do it with snappyHexMesh because it can handle it.

My suggestion for simplification is in the attachment. On the right hand side you see the spheres that touches at one point. On the LHS I just added cylinders to the connection therefore, it is easier to mesh. I would make it even bigger but that depend on how this will finally influence the solution.


I hope it is clear now.
Attached Images
File Type: jpg spheres.jpg (196.4 KB, 123 views)
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Old   April 26, 2016, 09:31
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Ok ..I got it..Just for clarification, the meshing of the image you attached has tetra elements (right side bigger sphere). Is it unavoidable in snappyhexmesh
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Old   April 26, 2016, 10:04
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Hi,

this is not a mesh, it is just a surface triangulation (STL). There is no computational mesh in the pictures. If you use snappyHexMesh, please make a good surface mesh (I mean a good surface triangulation).
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Old   October 6, 2016, 08:31
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Could you please comment on this:

http://www.cfd-online.com/Forums/ans...t-contact.html
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Old   October 25, 2016, 05:46
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Hi Manu

Have a look at the following work which was presented at the recent OpenFoam Workshop in Portugal. Both the abstract and slides are available below. It looks very similar to your requirements. In this work, they generate a random distribution of packed spheres in a cylinder using Blender and its physics modelling capabilities, then export the surface as an STL, and use snappyHexMesh to generate a mesh of the void space.

Abstract
http://www.openfoamworkshop.org/asse...1_paper_26.pdf

Slides
http://www.openfoamworkshop.org/asse...es/OFWP026.pdf

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Brian
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Old   November 11, 2019, 07:08
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Quote:
Originally Posted by Dipsomaniac View Post
Hi Manu

Have a look at the following work which was presented at the recent OpenFoam Workshop in Portugal. Both the abstract and slides are available below. It looks very similar to your requirements. In this work, they generate a random distribution of packed spheres in a cylinder using Blender and its physics modelling capabilities, then export the surface as an STL, and use snappyHexMesh to generate a mesh of the void space.

Abstract
http://www.openfoamworkshop.org/asse...1_paper_26.pdf

Slides
http://www.openfoamworkshop.org/asse...es/OFWP026.pdf

Regards,
Brian
Dear Brian,

Your post interests me a lot. I want to generate the porous media too. I want to try the blender software. But I could not download them anymore. The abstract and slides are not available now. Could you share the pdf files again?

Best regards,
Chengan
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