Laminar Boundary Layer Control By Combined Blowing And Suction In The Presence Of Roughness PDF Download

At subsonic speeds, full length laminar flow and low drags were obtained up to high length Reynolds numbers on a thin straight, on a swept laminar suction wing and on a suction body of revolution. Moderately increased suction rates in the most critical region of a straight and a swept laminar suction wing enabled full chord laminar flow in the presence of external sound. Theoretical investigatiions are concerned with nonlinear boundary layer oscillations and stability investigations (assuming small disturbances) of a supersonic laminar boundary layer on a flat plate up to high supersonic speeds as well as on a highly swept supersonic low drag suction wing of low wave drag. On a supersonic flat laminar suction plate with and without weak incident shock waves, extensive laminar flow and low equivalent drags were obtained at M = 3 up to length Reynolds numbers of 26 x 1000000. Further supersonic low drag suction experiments on a suction body of revolution, on a 36 degree supersonic yawing wing, as well as on a 72 degree supersonic yawing wing (swept behind the Mach cone) of low wave drag, are described. The latter wing showed full chord laminar flow with a subsonic type pressure distribution at M = 2 and R sub C approximately equal to 1000000. (Author).