how did i deal with the boundary?
 

hi to all !
i want to simulate a oscillating water flume .it's a big u-tube .there are some water in the U-tube initially.i set the pessure boundary condition on the left ,and outflow boudary on the right ,but the results are new water is pured into the water flume.i want to use the varible pessure to make initial water oscillating?how to deal with the boundary?
wish your help!

if you see new water coming from the left boundary condition then you need to setup for that boundary a Fluid Fraction = 0.0, that means "air".