Evolution of laminar flow disturbances behind a step on a surface generated by its localized vibrations

Abstract

The formation and development of hydrodynamic disturbances generated by low-frequency vibrations of a local region on a flat plate behind a rectangular step in separated flow is investigated in a wind tunnel. The results are obtained at a small subsonic flow velocity using the hot-wire anemometry. It is established that the wall vibrations induce separation zone disturbances representing streaky structures accompanied by wave oscillation packets. Laminar boundary layer separation favors the wave packet growth followed by wall flow turbulization.