Problem in the definition of dynamic mesh zones
I have a simple channel with length = 2 mm, Height = 150 um. Inlet is a mass-flow inlet and the outlet is a pressure outlet. The liquid is water and the flow is laminar. The bottomwall (see picture) need to move up and down (along y) in order to generate pressure waves that propagate in y direction. The movement of the bottomwall mimics the effect of a piezoelectric transducer.
My problem is that when the bottomwall moves, a perturbation origins at the outlet maybe for a conflict between the pressure condition that is fixed and the variation in pressure of the waves.
So I thought to move only a part of the bottomwall (figure below, black line stand for moving part of the wall, blue line represents the part of the wall where the condition of dynamic mesh is not applied), but in this way I have a jump in the condition applied to the bottomwall: on the moving part I set dynamic mesh (rigid body), on the other part I don't know how to define it. (If i put stationary, I have a perturbation).