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how to mesh a cylinder fixed in water tank

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Old   April 23, 2012, 20:09
Default how to mesh a cylinder fixed in water tank
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hi,

I would to add a cylinder(fixed) in the middle of a wave tank, how to do the mesh generation?
I learned from tutorial "flow around a cylinder" http://www.foamcfd.org/Nabla/guides/...Guidese12.html
and divided the tank into 20 blocks.

The first problem is about "inequality of cells number between neighbour blocks" I dont quite understand about how to set the red part of each block, the order or the numbers after it:

hex (4 9 10 5 23 28 29 24) (100 20 50) simpleGrading (1 1 1)

The second problem is after mesh generation (I just set all the numbers of cells in each direction equals the same) I use waveFOAM to generate wave and finally I got floating point exception issue, i am not sure if it is caused by wrong mesh generation, is there any way to solve it?

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Old   April 24, 2012, 02:11
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Hi,

Would you like to take another approach of importing "cylinder.STL" file and meshing around it , instead of generating the way described in above link ? ( Mostly this is approach i take!! )
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Old   April 24, 2012, 03:37
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Quote:
Originally Posted by kid View Post
Hi,

Would you like to take another approach of importing "cylinder.STL" file and meshing around it , instead of generating the way described in above link ? ( Mostly this is approach i take!! )
hi,

Thanks for ur reply,Could you link me a tutorial about your approach since I am fresh to cfd software and have no idea what is "cylinder.STL".

Many thanks
Vricc
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Old   April 24, 2012, 03:59
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Ok
Do you have geometry modeling software.
"cylinder.stl" It is just a name , it can be a cylinder generated using geometry modeling software.
"xyz.stl" here stl is a format in which a given geometry could be imported in OpenFOAM.

So my question is again do u have modeling s/w?
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Old   April 24, 2012, 04:06
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Quote:
Originally Posted by kid View Post
Ok
Do you have geometry modeling software.
"cylinder.stl" It is just a name , it can be a cylinder generated using geometry modeling software.
"xyz.stl" here stl is a format in which a given geometry could be imported in OpenFOAM.

So my question is again do u have modeling s/w?
No, I don't have any.
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Old   April 24, 2012, 04:14
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Then get one .
"Salome" is a free-ware.
Then we can discuss.

Here is a image of your case generated in OpenFOAM.
Attached Images
File Type: png cylinder.png (5.1 KB, 42 views)
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Old   April 24, 2012, 05:26
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Quote:
Originally Posted by kid View Post
Then get one .
"Salome" is a free-ware.
Then we can discuss.

Here is a image of your case generated in OpenFOAM.
Thanks for your information,
Btw, could you send me the original file of this image and how to combine this with blockMeshDict in openfoam?

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Old   April 24, 2012, 07:27
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@ llh
Yes, why not find a sample case.

Here
http://db.tt/Fsn0siFa

Note: make suitable changes for your case.
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Old   April 24, 2012, 08:36
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Thanks again for you help
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Old   April 24, 2012, 18:26
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Simple geometries such as this one can be also generated using paraview-->sources, then use the triangulate filter and then save data to save as a .stl

Anyway seems like you are having problems even with blockMesh, I would suggest you to read at least the first part of the openFoam manual before doing anything else…
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Old   April 30, 2012, 11:49
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If you will be using snappyHexMesh to get the mesh around the cylinder you don't need an stl, just use searchableCylinder.

//Björn
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