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cartesian vs cylindrical coordinate
Posted Oct 25, 2012, 8:08 a.m. EDT Version 4.2 2 Replies
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Hi
My problem is flow through a pipe surrounded by a rectangular block. Now I want to solve 3-D continuity, momentum and energy equations. Now, those equations need to be solved in cylindrical coordinate system for pipe and only energy equation need to be solved in Cartesian coordinate system for rectangular block.
Once open comsol model builder window after selecting the 3-D option, by default it is showing (x ,y, z) coordinate, that's fine when I am solving energy equation for rectangular block. But, (x, y, z) coordinate system can not be used for solving cylindrical system.
how can I resolve the issue?
rgds
Anup
2 Replies Last Post Oct 26, 2012, 10:31 a.m. EDT
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Posted:
1 decade ago
Hi
Sometims you can make a first model1 in 2D-axi, and project the result onto another model-2 in 3D.
But then you need also to project back the rest of the return flux exchange from the 3D to the 2D-axi model
--
Good luck
Ivar
Sometims you can make a first model1 in 2D-axi, and project the result onto another model-2 in 3D.
But then you need also to project back the rest of the return flux exchange from the 3D to the 2D-axi model
--
Good luck
Ivar
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Posted:
1 decade ago
Hi, Anup,
Your problem has no axial-symmetry, thus it should be an error to use that geometry. Nevertheless, if you are interested in the cylindrical coordinates, you can still define a Cylindrical System in Model/Definitions/Coordinate Systems, and use it in the corresponding physics / "Coordinate system selection". I think this is useful only to express anything as a function of these new coordinates (r, phi, a), referred to as sys2.r, etc, although the equations of your physics will be expressed only in cartesian coordinates (for instance, as far as I know only cartesian components are available for vector magnitudes).
Jesus.
Your problem has no axial-symmetry, thus it should be an error to use that geometry. Nevertheless, if you are interested in the cylindrical coordinates, you can still define a Cylindrical System in Model/Definitions/Coordinate Systems, and use it in the corresponding physics / "Coordinate system selection". I think this is useful only to express anything as a function of these new coordinates (r, phi, a), referred to as sys2.r, etc, although the equations of your physics will be expressed only in cartesian coordinates (for instance, as far as I know only cartesian components are available for vector magnitudes).
Jesus.