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-   -   Symmetryplane, cyclic and wedge boundary conditions (http://www.cfd-online.com/Forums/openfoam-pre-processing/94025-symmetryplane-cyclic-wedge-boundary-conditions.html)

 Taltan November 3, 2011 08:11

Symmetryplane, cyclic and wedge boundary conditions

I am a bit confused as to what the difference between these boundary conditions are. Any help would be appreciated. My take on these BC's:

1) SymmetryPlane
Mirrors along a plane so to reduce the amount of cells needed for a full model. For instance you have a model of a car, then you would only need to compute half of the car as the other half is symmetric.
2) Cyclic
Looping back information from one bc to another. For instance a pipe, where the outlet loops back to the inlet.
3) Wedge
This is the one I am the least confident about. Apparently this is only for 2D simulations for axisymmetric problems, for instance a pipe. But I though (hoped) that it was a way to reduce amount of cells in an axisymmetric 3D problem where you would only need to model a fraction of the pipe.
In the case I am working on I have a pipe which is axisymmetric with about 4 million cells and I wish to reduce this amount. Intuitively the wedge approach seemed good as I would only need the mesh for a small section of the pipe. However if this is only for 2D then my simulation would probably fall apart as I intend to model LES.

So hopefully the symmetryPlane approach would work in my case perhaps? Where I would revolve my pipe only 180 degrees and use symmetryPlane bc on the resulting flat surface.

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