3D sphere - blockMesh
 

Hi,

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

Thanks,
Ben

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

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

SwiftBlock should be the easiest...

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,
Eloïse

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

Hi Kalle,

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

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,
Eloïse

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

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

You mentioned that you: But then you state that you got:
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

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

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. :)

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.

Chun, do you mean something like this??

http://www.cfd-online.com/Forums/ope...tml#post523468

Dear kalle,

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

Chun

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