[philferdinand]

Dear FOAMers,

My goal is to simulate a pressure wave (water hammer) on a guide vane in a stream channel (to eventually calculate the lift and drag forces on that guide vane). I have little to no experience with compressible solvers but sonicLiquidFoam (OF V3.0.0) seemed like the right choice given that the tutorial deals with a water hammer and that it is actually suitable for water as a fluid.

So my idea is to simulate the flow around the guide vane with a given velocity (to know the lift and drag in normal operation) and then at one point to increase the inlet pressure at the inlet to simulate the arriving pressure wave.

The problem is that I can not get a steady state flow around the turbine blade since the initial pressure field that builds up around the blade creates a pressure wave which oscillates in the channel and can't exit on any of the boundaries (neither inletOutlet nor zeroGradient for the outlet let the pressure exit).

I would like the pressure waves to exit through In- and Outlet without reflecting and found the waveTransmissive boundary condition. Anyhow this BC does not seem applicable in sonicLiquidFoam, since there is no psi field written.

This here (http://www.cfd-online.com/Forums/ope...oam-crash.html) gave me the idea that I could add a psi field to the setFields.C, since psi is actually set in the thermodynamicProperties, but it doesn't seem to be that easy.

Does one of you have an idea how to:

a) how to implement the waveTransmissive BC in sonicLiquidFoam OR
b) what other BC would let the pressure waves pass OR
c) which other solver would be better suited for the problem

I thank you very much for your help and hope that I have formulated my question adequately

guideVane.jpg