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3D sphere - blockMesh

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Old   August 21, 2012, 01:42
Default 3D sphere - blockMesh
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bmt
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Hi,

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

Thanks,
Ben
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Old   August 23, 2012, 14:43
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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" See tutorial: "potentialFoam/cylinder/constant/polyMesh/blockMeshDict"
Best regards,
Bruno
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Old   August 23, 2012, 20:59
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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
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Old   August 24, 2012, 17:52
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SwiftBlock should be the easiest...
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Old   February 23, 2013, 17:33
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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
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Old   February 25, 2013, 02:48
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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
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Old   February 25, 2013, 09:08
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Hi Kalle,

Quote:
Originally Posted by kalle View Post
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
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Old   February 25, 2013, 10:34
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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.
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File Type: zip Example-External_Sphere.m4.zip (7.8 KB, 294 views)
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Old   February 25, 2013, 10:45
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Quote:
Originally Posted by startingWithCFD View Post
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
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Old   October 20, 2014, 20:25
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i made a sphere using only blockmesh. the pic is attached, it is an egg, with a hemisphere at the bottom
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Old   October 26, 2014, 11:40
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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
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Old   November 1, 2014, 14:45
Default making 3D-sphere
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ali naqi mohammadi
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hi
i made sphere by using toposetDict!
it just needs to define radius and center of sphere
but it needs too many cells
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Old   July 29, 2016, 17:54
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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.
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Old   July 29, 2016, 19:47
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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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Old   July 30, 2016, 08:01
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Chun, do you mean something like this??

http://www.cfd-online.com/Forums/ope...tml#post523468
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Old   July 30, 2016, 17:23
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Dear kalle,

Yes! Your mesh looks perfect!! Thank you so much!
I will study your post.

Chun
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Old   October 14, 2016, 07:40
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Mr. Weller released an implementation and a tutorial for meshing a sphere with a single block in his dev repository. Right now I have no time to have a try but to me it looks very promising.

https://github.com/OpenFOAM/OpenFOAM...8a22a6d58be0ba
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