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Old   October 10, 2011, 06:58
Default cylindrical mesh
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Marcin
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Why when using cylindrical mesh there is a plane 1 and 2, so the contact is from 0 - 360 degrees. I have uploaded two pictures demonstrating the problem. And my Q is how to eliminate this line.
1.
http://imageshack.us/photo/my-images/255/27918353.jpg/
2.
http://imageshack.us/photo/my-images/607/33350229.jpg/
BSR
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Old   November 21, 2011, 07:46
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Giacomo Vi
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I have the same problem. The grid seems to be not perfectly closed on 0-360. The computation is affected by giving results not accectable in my case. Does anyone know how to guarantee a perfect closure of the cylindrical mesh? Thx Giacomo
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Old   November 30, 2011, 14:44
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Jeff Burnham
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See the question and answer about periodic boundaries.
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Old   September 11, 2013, 03:07
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is this problem solved? plz help
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Old   September 11, 2013, 11:45
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Jeff Burnham
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There's not a problem. In cylindrical coords, like in Cartesian, there are always six boundary conditions per mesh block. The boundaries don't close up. Instead, you set the y-boundaries to 'periodic'. Whatever fluid, scalars, particles, etc. cross out of one y-boundary appear at the same elevation at the opposite boundary. This lets you make a quarter-model of a cylindrical tank without modeling the entire tank space, for instance. If you wrap the mesh 360 degrees around the axis, then you're modeling the whole tank, but you still use periodic boundaries to represent the connection between one end of the mesh and the other.
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Old   September 11, 2013, 12:15
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thank friend for your response
im studying a hydrocyclone in which we have rotary flow, this method works there? and another thing , u mean in cylindrical coordination the Ymax and Ymin represent the two starting and ending surfaces of cylindrical mesh?

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Old   September 11, 2013, 15:08
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Jeff Burnham
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Yes, the Pd-boundaries in y work for rotating flow, and have been used for cyclonic modeling with FLOW-3D. - Jeff
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