Changing BC from Opening to Wall during Solving
 

Dear Friends,

I have a chamber which has with two valves. I want to perform my CFD analysis in two phases. At the first phase fluid flows into chamber through valve no.1 which is Velocity Inlet and the valve no.2 is closed (wall). In the second phase the valve no.2 opens (I would like to change it to Opening with Pressure) and let the fluid goes out and the valve no.1 is closed (wall). My problem is that I could not find an automatic way to change the boundary from Wall to Opening during the solving process.

I would appreciate if some one give a hint.

Thank you Ahmad