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-   OpenFOAM Native Meshers: blockMesh (http://www.cfd-online.com/Forums/openfoam-meshing-blockmesh/)
-   -   3D sphere - blockMesh (http://www.cfd-online.com/Forums/openfoam-meshing-blockmesh/106156-3d-sphere-blockmesh.html)

bmt August 21, 2012 01:42

3D sphere - blockMesh
 
Hi,

Does anyone know a way of meshing a 3D sphere using only blockMeshDict? Is this even possible? :confused:

Thanks,
Ben

wyldckat August 23, 2012 14:43

Greetings Ben,

I think it's not impossible, but it's probably very arduous to do. There are a few solutions I can think of:
  • Do it interactively: http://openfoamwiki.net/index.php/Contrib/SwiftBlock
  • Cheat by using snappyHexMesh, as shown in the tutorial "mesh/snappyHexMesh/iglooWithFridges".
  • Use Plot3D format to design the mesh, then convert with datToFoam and then run blockMesh.
  • Use OpenFOAM's codeStream and code it directly into "blockMeshDict" :cool: See tutorial: "potentialFoam/cylinder/constant/polyMesh/blockMeshDict"
Best regards,
Bruno

bmt August 23, 2012 20:59

Hi,

Thanks for that I will give it a go. I am looking to make a structured mesh to compare results against snappyHexMesh. Which of the above methods would be best for this purpose?

Thanks

wyldckat August 24, 2012 17:52

SwiftBlock should be the easiest...

Eloise February 23, 2013 17:33

Hi Ben,

Did you manage to do a 3D sphere in blockMesh? If so, I'd be interested to know how you did so :)

Thanks,
Elo´se

kalle February 25, 2013 02:48

Hi,

my guess is that it is not possible without a blockMesh that can snap to surfaces (such a blockMesh does not exist as far as I know).

K

wyldckat February 25, 2013 09:08

Hi Kalle,

Quote:

Originally Posted by kalle (Post 409868)
my guess is that it is not possible without a blockMesh that can snap to surfaces (such a blockMesh does not exist as far as I know).

Strange... I though that with arcs and since wedges can be created, it should be possible to create a discrete sphere that is built with slices...

Best regards,
Bruno

startingWithCFD February 25, 2013 10:34

1 Attachment(s)
In my archives I found the attached file. It was downloaded from somewhere in this forum (can't remember where and I have actually renamed the file :-/ Apologies to the original creator for not giving credit). I know that it should normally have a cubic block in the middle, but hey, it's a start. I hope it helps.

Eloise February 25, 2013 10:45

Quote:

Originally Posted by startingWithCFD (Post 409952)
In my archives I found the attached file. It was downloaded from somewhere in this forum (can't remember where and I have actually renamed the file :-/ Apologies to the original creator for not giving credit). I know that it should normally have a cubic block in the middle, but hey, it's a start. I hope it helps.

Thanks a lot! I will have a look at it as soon as I have time :)
Regards,
Elo´se

sulemankhan22 October 20, 2014 20:25

1 Attachment(s)
i made a sphere using only blockmesh. the pic is attached, it is an egg, with a hemisphere at the bottom

wyldckat October 26, 2014 11:40

Greetings to all! And sulemankhan22, welcome to the forum!

You mentioned that you:
Quote:

made a sphere using only blockmesh
But then you state that you got:
Quote:

it is an egg, with a hemisphere at the bottom
Did you get this egg shape because you wanted, or do you believe that something went wrong?

If you believe something went wrong, then please share the "blockMeshDict" file you have.

Best regards,
Bruno

ali naqi November 1, 2014 14:45

making 3D-sphere
 
hi
i made sphere by using toposetDict!
it just needs to define radius and center of sphere
but it needs too many cells

chun July 29, 2016 17:54

Dear sulemankhan22, Dear ali naqi,

It is possible that I can know your method to build a 3D sphere mesh? I am interested about the mesh and the way to make it. :)

Phyonth July 29, 2016 19:47

You can use snappyHexMesh to build a 3-D spher mesh. Either just a sphere or remove a spherical part from your domain. check this thread : "simple sphere with snappyhexmesh", might be useful.


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