Аннотация:This paper present a numerical study of a free-molecular (Kn >10) gas flow in two devices with high-frequency oscillating boundary: (1) flow in plane channel with a series of oscillating barriers. (2) flow in a channel with wall performing forced harmonic motion. All calculations were performed using simplified collision-free version of Event-Driven Molecular Dynamics method (EDMD). It was shown that high-frequency oscillations have a significant influence on the gas flow, and this influence depends on molecules characteristic thermal speed. Thus it was shown, that this influence will be different for gases with different molecular masses, which leads to gas separation effect.