symmetry and wall (free slip) BC
Hi,
What is the difference between symmetry and free slip wall boundary conditions in ANSYS CFX. |
This is described in the documentation.
Symmetry enforces zero normal gradient to all parameters, and a slip wall does not necessarily do this. But for most normal simulations they are equivalent. And a symmetry plane is required to be planar, but a slip wall can be any shape. |
@ghorrocks : Some body showed a case of cylindrical shape domain and he has applied symmetry condition for the 60 deg sector. In my understanding symmetry condition reflect the solution around the mirror plane which in my understating can only be applied to two planes in 3-d case. I suggested him the periodic bc instead.
What do you think? |
I did not double-check if this is true in CFX. Another difference between the two boundary types should show up when using a turbulence model.
Near a free-slip wall, the turbulence kinetic energy is zero while at a symmetry boundary condition its normal gradient is zero. |
Quote:
This is taken from CFX help : Quote:
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2 Attachment(s)
and this is from the fluent help (same meaning as shown in CFX help ) and which is very much clear...
http://www.cfd-online.com/Forums/att...1&d=1440093732 Fluent help on symmetry BC: http://www.cfd-online.com/Forums/att...1&d=1440094135 |
Quote:
That is the key difference to keep in mind for symmetry versus periodic. |
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