HYDRODYNAMIC STRUCTURES - ELEMENTS OF THE SELF-SUSTAINED OSCILLATION SYSTEM IN THE FLOW

摘要

The character of hydrodynamic disturbances in the near-wall shear flow inducing self-oscillations in the channel has been investigated. Experiments have been performed in a small and a large wind tunnel at a flow velocity of 10-40 m/sec. It has been found that excitation of self-oscillations becomes possible as a result of narrow-band acoustic radiation generation by not only vortex formations but also large-scale coherent structures in the region of the laminar-turbulent transition and in the turbulent boundary layer.