# Meshing a circle

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 May 13, 2008, 11:24 Hello World. I thought abou #1 Senior Member     Sebastian Gatzka Join Date: Mar 2009 Location: Frankfurt, Germany Posts: 729 Rep Power: 12 Hello World. I thought about this solution to create a spherical mesh. Unfortunately it contains some stretched elements. Do you think this is the best of maybe the only way of creating a spherical grid? __________________ Schrödingers wife: "What did you do to the cat? It's half dead!"

 May 13, 2008, 11:25 Sorry, there was a problem wit #2 Senior Member     Sebastian Gatzka Join Date: Mar 2009 Location: Frankfurt, Germany Posts: 729 Rep Power: 12 Sorry, there was a problem with the upload. __________________ Schrödingers wife: "What did you do to the cat? It's half dead!"

 May 13, 2008, 12:05 Hi Sebastian I have come to #3 Senior Member   Niels Gjoel Jacobsen Join Date: Mar 2009 Location: Deltares, Delft, The Netherlands Posts: 1,702 Rep Power: 27 Hi Sebastian I have come to think about it, and if you make a block with "corners" in 45, 135, 225 and 315 degrees and make arcs which connects to 0, 90, 180 and 270 degrees, then you will get a perfect circle. Best regards, Niels __________________ Please note that I do not use the Friend-feature, so do not be offended, if I do not accept a request.

 May 13, 2008, 12:43 What we used to do, is to put #4 Senior Member   Eugene de Villiers Join Date: Mar 2009 Posts: 725 Rep Power: 13 What we used to do, is to put all the block points except the one on the axis on the same radius from the axis. There is still some distortion, but less than what you have. I.e. if the square block is defined by 2----3 |......| |......| 0----1 And the coordinates are p0 = (0, 0, 0) p1 = (1, 0, 0) p2 = (0, 1, 0) Then p3 = (sqrt(0.5), sqrt(0.5), 0) not p3 = (1, 1, 0) like you have it.

 May 13, 2008, 13:08 Hi Sebastian, I think you w #5 Senior Member   Cedric DUPRAT Join Date: Mar 2009 Location: Belgium Posts: 185 Rep Power: 9 Hi Sebastian, I think you will find what you are looking for here : http://openfoamwiki.net/index.php/Si...e_next_meeting there, you will find an sourceForge adress where all the cases are avaiable. (http://openfoam-extend.svn.sourceforge.net/svnroot/openfoam-extend/trunk/Breeder /OSIG/TurboMachinery/ercoftacConicalDiffuser) These are not just pipes but, you can modify (m4 files) the mesh file easily to get what you want. there are lot of parameters avaiable to make your own mesh. I hope it will be helpfull Cedric

 May 14, 2008, 02:56 Now I get it. You mean someht #6 Senior Member     Sebastian Gatzka Join Date: Mar 2009 Location: Frankfurt, Germany Posts: 729 Rep Power: 12 Now I get it. You mean somehting like that: __________________ Schrödingers wife: "What did you do to the cat? It's half dead!"

 May 14, 2008, 03:57 Exactly. I know its not ideal, #7 Senior Member   Eugene de Villiers Join Date: Mar 2009 Posts: 725 Rep Power: 13 Exactly. I know its not ideal, especially at the 3 block junction, but I think it is the best compromise given the available resources.

 May 23, 2008, 11:06 Hey. Me again. So, I did it #8 Senior Member     Sebastian Gatzka Join Date: Mar 2009 Location: Frankfurt, Germany Posts: 729 Rep Power: 12 Hey. Me again. So, I did it and created a circular mesh out of about 20 hex-blocks: The problem is, that when I'm trying to solve my problem on this grid I get this message: --> FOAM FATAL ERROR : This mesh contains patches of type empty but is not 1D or 2D by virtue of the fact that the number of faces of this empty patch is not divisible by the number of cells. I'm not sure what to think, but is this because of the internal faces connecting the blocks? I read the User Guide about Miltiple Blocks but I'm not sure I understood it. Maybe I'm not, because I don't know if my problem has something to do with this... If you want to have a look: http://therealsega.th.funpic.de/open...ourMesh.tar.gz Thanks so far! __________________ Schrödingers wife: "What did you do to the cat? It's half dead!"

 May 23, 2008, 11:13 Sorry, the Image was too large #9 Senior Member     Sebastian Gatzka Join Date: Mar 2009 Location: Frankfurt, Germany Posts: 729 Rep Power: 12 Sorry, the Image was too large. http://therealsega.th.funpic.de/openfoam/mesh.png __________________ Schrödingers wife: "What did you do to the cat? It's half dead!"

 May 24, 2008, 06:15 Hello, Theres a face missin #10 Senior Member     Jose Luis Santos Join Date: Mar 2009 Location: Portugal Posts: 215 Rep Power: 10 Hello, Theres a face missing in your patch fixedWalls. Open your case in Paraview, and you'll see that there is a face at the top that is not included in fixedWalls, rather in defaultFaces. Regards, Jose Santos

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