Effect of predominantly unidirectional flow of a viscous liquid between solid walls

The problem is considered on a flow of a viscous liquid in the presence of solid bodies - two walls and a free plate the boundary of which is permeable for a liquid - under oscillatory influences. The formulation of the problem includes the equation of the plate motion, the equations of Navier-Stokes and a continuity and conditions at solid boundaries of the liquid. The new hydro-mechanical effect is revealed which consists in that in the absence of a predominant direction in space free parts of the hydro-mechanical system at a background of oscillations perform a unidirectional, steady motion.