[blockMesh] 3D sphere - blockMesh

bmt · August 21, 2012, 01:42

Hi,

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

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" 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, 16:33

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,
Eloïse

kalle · February 25, 2013, 01:48

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, 08:08

Hi Kalle,

Quote:

Originally Posted by kalle

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, 09:34

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, 09:45

Quote:

Originally Posted by startingWithCFD

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

sulemankhan22 · October 20, 2014, 20:25

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, 10:40

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, 13:45

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.

kalle · July 30, 2016, 08:01

Chun, do you mean something like this??

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

chun · July 30, 2016, 17:23

Dear kalle,

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

Chun

Traction · October 14, 2016, 07:40

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

August 21, 2012, 01:42	3D sphere - blockMesh	#1
bmt New Member Join Date: Aug 2012 Posts: 3 Rep Power: 13	Hi, Does anyone know a way of meshing a 3D sphere using only blockMeshDict? Is this even possible? Thanks, Ben

August 23, 2012, 14:43		#2
wyldckat Retired Super Moderator Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 10,974 Blog Entries: 45 Rep Power: 128	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 babakflame likes this. __________________ OpenFOAM: FAQ \| Getting started Forum: How to get help, to post code/output and forum guide Read this before sending me PM

August 24, 2012, 17:52		#4
wyldckat Retired Super Moderator Bruno Santos Join Date: Mar 2009 Location: Lisbon, Portugal Posts: 10,974 Blog Entries: 45 Rep Power: 128	SwiftBlock should be the easiest... __________________ OpenFOAM: FAQ \| Getting started Forum: How to get help, to post code/output and forum guide Read this before sending me PM

November 1, 2014, 13:45	making 3D-sphere	#12
ali naqi New Member ali naqi mohammadi Join Date: Dec 2012 Posts: 6 Rep Power: 13	hi i made sphere by using toposetDict! it just needs to define radius and center of sphere but it needs too many cells

October 14, 2016, 07:40		#17
Traction Member Join Date: Mar 2014 Posts: 39 Rep Power: 12	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 wyldckat and olegrog like this.

August 23, 2012, 20:59		#3
bmt New Member Join Date: Aug 2012 Posts: 3 Rep Power: 13	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

February 23, 2013, 16:33		#5
Eloise Senior Member Eloïse Join Date: Jul 2012 Location: Trondheim, Norway Posts: 113 Rep Power: 13	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

February 25, 2013, 01:48		#6
kalle Senior Member Karl-Johan Nogenmyr Join Date: Mar 2009 Location: Linköping Posts: 279 Rep Power: 21	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

July 29, 2016, 17:54		#13
chun New Member Join Date: Jun 2014 Posts: 22 Rep Power: 11	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.

July 29, 2016, 19:47		#14
Phyonth New Member Join Date: Oct 2014 Posts: 4 Rep Power: 11	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.

July 30, 2016, 08:01		#15
kalle Senior Member Karl-Johan Nogenmyr Join Date: Mar 2009 Location: Linköping Posts: 279 Rep Power: 21	Chun, do you mean something like this?? http://www.cfd-online.com/Forums/ope...tml#post523468

July 30, 2016, 17:23		#16
chun New Member Join Date: Jun 2014 Posts: 22 Rep Power: 11	Dear kalle, Yes! Your mesh looks perfect!! Thank you so much! I will study your post. Chun

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