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-   -   how to mesh a cylinder fixed in water tank (http://www.cfd-online.com/Forums/openfoam/100311-how-mesh-cylinder-fixed-water-tank.html)

lilinghan8 April 23, 2012 20:09

how to mesh a cylinder fixed in water tank
 
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?

Regards,
Vricc

kid April 24, 2012 02:11

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!! )

lilinghan8 April 24, 2012 03:37

Quote:

Originally Posted by kid (Post 356574)
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

kid April 24, 2012 03:59

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?

lilinghan8 April 24, 2012 04:06

Quote:

Originally Posted by kid (Post 356601)
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.

kid April 24, 2012 04:14

1 Attachment(s)
Then get one .
"Salome" is a free-ware.
Then we can discuss.

Here is a image of your case generated in OpenFOAM.

lilinghan8 April 24, 2012 05:26

Quote:

Originally Posted by kid (Post 356604)
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?

Regards,
Vricc

kid April 24, 2012 07:27

@ llh
Yes, why not find a sample case.

Here
http://db.tt/Fsn0siFa

Note: make suitable changes for your case.

lilinghan8 April 24, 2012 08:36

Thanks again for you help

lovecraft22 April 24, 2012 18:26

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…

winden April 30, 2012 11:49

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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