Hi I have some doubts regar
 

Hi

I have some doubts regarding the symmetryPlane boundary condition:

1) What exactly is it? How do the fields and derivatives behave across a boundary with the symmetryPlane condition?

2) When solving for external flows in a rectangular domain (say, flow around an airfoil), it has been recommended that the left boundary be the inlet, the right be the outlet and the top and bottom boundaries be prescribed the symmetryPlane boundary condition. Why is the symmetryPlane condition used here?

3) In the cylinder example given in the potentialFoam tutorial, the surface of the cylinder is prescribed the symmetryPlane boundary condition. It has to be reflected to complete the cylinder, but must it not also be specified as a wall? And the initial Pressure and Velocity conditions (in the 0 time folder) also specify the boundary condition type as symmetryPlane. What does this mean?

Thank you for helping.