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Old   January 25, 2007, 06:44
Default 2D Simulations
  #1
Uros
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Hallo everybody!

Does anyone know how to create a 2D (quasi) simulation in CFX10? The help file says it's possible, but following those steps I always get a message: "CFX can only operate on Solid Volumes!". I want to create a simple planar rectangular surface with one moving boundary, no inlets and outlets and simulate gas behaviour bounded by the geometry.

Thanks a lot for any replies! Greetings,

Uros.
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Old   January 25, 2007, 07:47
Default Re: 2D Simulations
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Joe
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Use the forum search function.
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Old   January 25, 2007, 17:27
Default Re: 2D Simulations
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Santiago Orrego.
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You have to extrude, 1 cell deep, in your mesh software.
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Old   January 26, 2007, 08:07
Default Re: 2D Simulations
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tarek
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You need to create a volume, to simulate 2D simulation, so u have to choose one unite in the Z direction, and ur reall values in the (x,y) direction. Tarek
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Old   January 27, 2007, 05:30
Default Re: 2D Simulations
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Deepak Narayan Ramanath
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Basically, you have to know that CFX is a 3-D solver and not a 2-D, therefore, you need to have a 3-D mesh for CFX. For simulating 2-D, extrude the mesh (one cell thick) in the Z direction. Or if you are trying to do a 2-D axisymmetry, then extrude by rotation by say 1 degree or max 5-degree, depending on the complexity of the model. Since you would be having a slip-wall boundary condition on those extruded symmetry faces, the fluxes calculated are equated to 0. This acts as symmetry BC.
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Old   January 29, 2007, 14:36
Default Re: 2D Simulations
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Robin
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Don't use a free slip wall, use Symmetry or, if there is swirl, create a Periodic interface.

-Robin
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Old   January 29, 2007, 21:22
Default Re: 2D Simulations
  #7
Bak_Flow
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Why not Robin....?

Regards,

Bak_Flow
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Old   February 24, 2007, 09:04
Default Re: 2D Simulations
  #8
Robin
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Hi Bak_Flow,

There is a subtle difference in the discretization at the wall. A free slip wall will not enforce a zero gradient, whereas a symmetry plane will. How the solver does this also affects the calculation of gradients which are used for second order terms. To make a long story short, if you have a grid one element thick and use a free slip wall the advection term will only be first order upwind. So use symmetry.

Regards, Robin
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