[blockMesh] Meshing a disc like this

m_r · May 7, 2012, 04:43

Hello everyone !

I'm a new user of OpenFOAM and I wish realise a mesh of this type, but i don't really know how to do it :

Somebody can help me to start ?

I have understood how to mesh differents types of cubes (such as with an arc of circle) but i have no idea for start to mesh a circle/a disc.

Thank you (and sorry for my bad english

)

Marine

romant · May 7, 2012, 04:53

I don't think you will be able to mesh this with blockMesh, because blockmesh will create hexahedral cells, however exactly at the center you have tetrahedral cells. the easiest way to create such a disc is to make a block in the center and then create quarter circle blocks on every side.

m_r · May 7, 2012, 05:10

Thank for your rapid answer.

If I understood correctly,, your idea is to create a central block then create many quarter circle block around.

You think it's possible to realise a maillage like this with four blocks and create arcs of circle inside the blocks ?

romant · May 7, 2012, 05:20

I think the following can help you. You can create arc also on the inside of the block, but you won't have a disc then, but a ring, which has just a very small hole in the center. 5 blocks (1 center block, 4 blocks on the outside, where the ones on the outside have arcs as boundaries) is the standard to create round objects with hexahedral cells.

http://www.cfd-online.com/Forums/ope...arge-mesh.html

m_r · May 7, 2012, 05:26

Thank, I studying your link and then, after, I try to meshing a disc.

Ivanet · May 7, 2012, 08:08

It is possible and even very easy to do it with blockMesh.
You can check for example this link
http://www.somogyibence.hu/documents...sh_O-Grid.html
for learning about how to work with blockMesh.

Greetings
Ivan

m_r · May 7, 2012, 08:50

Thank you so much Ivan.

Nikunj.R · July 18, 2012, 14:52

1.Divide the circle in 4 quadrants, assume the point (0,0,0) to be at the center of the disc.
2.find the coordinates of all the vertices of the quadrants relative to this point. (eg: (5,0,0) (0,5,0) (-5,0,0) (0,-5,0).
3. specify the same vertices for say z=10
4.specify that edges 0-1. 1-2, et al are arcs, while following the correct syntax.
5.form the block.
6. give "empty" bc for faces at z=10, z=-10.

May 7, 2012, 04:43	Meshing a disc like this	#1
m_r New Member Marine Join Date: Apr 2012 Location: France Posts: 9 Rep Power: 13	Hello everyone ! I'm a new user of OpenFOAM and I wish realise a mesh of this type, but i don't really know how to do it : Somebody can help me to start ? I have understood how to mesh differents types of cubes (such as with an arc of circle) but i have no idea for start to mesh a circle/a disc. Thank you (and sorry for my bad english ) Marine Last edited by m_r; June 4, 2012 at 10:12.

May 7, 2012, 04:53		#2
romant Senior Member Roman Thiele Join Date: Aug 2009 Location: Eindhoven, NL Posts: 374 Rep Power: 20	I don't think you will be able to mesh this with blockMesh, because blockmesh will create hexahedral cells, however exactly at the center you have tetrahedral cells. the easiest way to create such a disc is to make a block in the center and then create quarter circle blocks on every side. __________________ ~roman

May 7, 2012, 05:20		#4
romant Senior Member Roman Thiele Join Date: Aug 2009 Location: Eindhoven, NL Posts: 374 Rep Power: 20	I think the following can help you. You can create arc also on the inside of the block, but you won't have a disc then, but a ring, which has just a very small hole in the center. 5 blocks (1 center block, 4 blocks on the outside, where the ones on the outside have arcs as boundaries) is the standard to create round objects with hexahedral cells. http://www.cfd-online.com/Forums/ope...arge-mesh.html __________________ ~roman

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May 7, 2012, 05:10		#3
m_r New Member Marine Join Date: Apr 2012 Location: France Posts: 9 Rep Power: 13	Thank for your rapid answer. If I understood correctly,, your idea is to create a central block then create many quarter circle block around. You think it's possible to realise a maillage like this with four blocks and create arcs of circle inside the blocks ?

May 7, 2012, 05:26		#5
m_r New Member Marine Join Date: Apr 2012 Location: France Posts: 9 Rep Power: 13	Thank, I studying your link and then, after, I try to meshing a disc.

May 7, 2012, 08:08		#6
Ivanet Member Join Date: Oct 2010 Location: Germany Posts: 39 Rep Power: 15	It is possible and even very easy to do it with blockMesh. You can check for example this link http://www.somogyibence.hu/documents...sh_O-Grid.html for learning about how to work with blockMesh. Greetings Ivan

May 7, 2012, 08:50		#7
m_r New Member Marine Join Date: Apr 2012 Location: France Posts: 9 Rep Power: 13	Thank you so much Ivan.

July 18, 2012, 14:52		#8
Nikunj.R Member Nikunj Raithatha Join Date: Jul 2012 Location: Washington DC Posts: 47 Rep Power: 13	1.Divide the circle in 4 quadrants, assume the point (0,0,0) to be at the center of the disc. 2.find the coordinates of all the vertices of the quadrants relative to this point. (eg: (5,0,0) (0,5,0) (-5,0,0) (0,-5,0). 3. specify the same vertices for say z=10 4.specify that edges 0-1. 1-2, et al are arcs, while following the correct syntax. 5.form the block. 6. give "empty" bc for faces at z=10, z=-10.