Control of Leading-Edge Flow Separation from Airfoils by Acoustic Excitation

Since several years experiments are carried out at DLR Goettingen to investigate the feasibility of controlling the laminar- turbulent boundary layer transition by means of periodic, in particular acoustic, excitation of the unstable laminar boundary layer. Similar techniques can be applied to diminish the flow separation from airfoils or to shift the onset of separation to higher angles of incidence. Work on this problem has been carried out by V.V. Kozlov and A.V. Dovgal of ITAM Novosibirsk in cooperation with the first author during their stay at Goettingen as guest scientists. The paper concern mainly windtunnel experiments on the control of three-dimensional separation from a wing by external acoustic excitation