mesh generation of porous media

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 March 3, 2015, 03:18 mesh generation of porous media #1 New Member   Eric Liu Join Date: Jan 2015 Posts: 6 Rep Power: 4 hi, everyone! I am new to openFoam. Though some simple cases with simple geometry can be done, many solvers and utilities are not familiar. I am trying to solve a 2D case of porous media, but stuck in generating the meshes. The blockMesh is not so useful for this problem. I get a txt file to tell the position of the solid and the pore, but do really not know how to generate the meshes. Should I use snappyHexMesh or other mesh generators? Anyone solving similar questions is welcome to give suggestions and I really appreciate your help!

May 27, 2015, 05:55
Porous media generation!!
#2
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Saideep
Join Date: Apr 2015
Location: INDIA
Posts: 177
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Hi Eric;

I am quite sure you cannot use blockMesh as it can only create more or less structured meshes with arc and splines etc but it would be useful if you can generate a 2D image of your pores or solids on inkscape or blender and convert it to a 3D .stl image and use it over snappyHexMesh.

I have the results something like this(figure 1) for a uniform pore geometry. But it is not of much help as when I inject a fluid at top it just flows quite fast and in the easiest path(straight).

So, next step I tried to create a non-homogeneous pore geometry. But it is surely not easy as when you try to generate the solids randomly there can be several connections inbetween the solids and your snappyhexmesh somehow covers only a small area.

Actually I am impressed by the way how Andrea Ferrari and Ivan Lunati created there random distributed solids in paper: Direct numerical simulations of interface dynamics to link capillary pressure and total surface energy.

Thanks
Saideep
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 figure 1.jpg (61.0 KB, 118 views) figure2.jpg (94.9 KB, 99 views)

May 27, 2015, 06:16
#3
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Saideep
Join Date: Apr 2015
Location: INDIA
Posts: 177
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I am interested to keep this thread alive and from my new model for a non-homogeneous porous medium it looks to get some sort of shape.

I had to refine the mesh so much (800*800) to get some sort of meaningful result for the porous medium that is randomly generated using inkscape(to generate random solids), blender (to convert .svg to .stl and from 2D to 3D) and snappyHexMesh to get the required model shape for analysis.

But the problem now is the time. As the dx is going so low, the Co number is too large and thereby ultimately it effects the time step size. However, I will just run basic simulation to see how the results vary from homogeneous case and will keep updated.

Thanks and waiting for any suggestions.
Saideep
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 figure3.jpg (43.2 KB, 68 views)

May 28, 2015, 08:18
#4
New Member

Eric Liu
Join Date: Jan 2015
Posts: 6
Rep Power: 4
hello, saideep:

i am glad that you reply to me. i am using snappyHexMesh to generate mesh for my porous media. the .stl file is obtained from the CT images, which i did some process.

the mesh is as follows.

the
Attached Images
 pore.jpg (74.5 KB, 255 views)

January 19, 2016, 15:22
#5
New Member

Join Date: Mar 2014
Posts: 23
Rep Power: 5
Hello Foamers,

I am new to OpenFOAM. I am trying to simulate a two-phase flow in porous medium using PorousInterFoam solver. I my case I have a permeable wall which I want to simulate it as a surface in which there are many holes so the the porous medium region is connected to the surface flow region. I am wondering if there is an easy way to do that. I am attaching a photo of my geometry for better understanding of my case.

Any help would be greatly appreciated.
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 Untitled.jpg (25.5 KB, 48 views)

February 24, 2017, 11:32
3-D porous media: twophase flow
#6
New Member

Kay
Join Date: Jan 2016
Posts: 5
Rep Power: 3
Hello All,

I have a three phase (solid, water, air) 3-D pore structure.
I also have the STL files for all three phases (solid, water, air) generated.
Any ideas how these phases can go directly into OpenFOAM with boundaries correctly delineated would be appreciated.

For the boundaries,
The top boundary is atmospheric (later I would have an infiltration boundary), the bottom is a fixedpressure (water would either drain by gravity or rise by capillarity depending on the direction of pressure step down or step up) boundary and the sides are walls (no flow).

I look forward to your input.

Thank you.

Quote:
 Originally Posted by Saideep Hi Eric; Though I realise yours is an old thread, did you succeed in accomplishing your task? I am quite sure you cannot use blockMesh as it can only create more or less structured meshes with arc and splines etc but it would be useful if you can generate a 2D image of your pores or solids on inkscape or blender and convert it to a 3D .stl image and use it over snappyHexMesh. I have the results something like this(figure 1) for a uniform pore geometry. But it is not of much help as when I inject a fluid at top it just flows quite fast and in the easiest path(straight). So, next step I tried to create a non-homogeneous pore geometry. But it is surely not easy as when you try to generate the solids randomly there can be several connections inbetween the solids and your snappyhexmesh somehow covers only a small area. Actually I am impressed by the way how Andrea Ferrari and Ivan Lunati created there random distributed solids in paper: Direct numerical simulations of interface dynamics to link capillary pressure and total surface energy. If you already have any idea please do share. Thanks Saideep

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