Leading-edge rotating cylinder for boundary-layer control on lifting surfaces

Wind tunnel experiments are conducted to study the boundary layer control attained on a symmetrical afterbody by means of a rotating cylinder at its leading edge. Experimental results indicate that a rotating cylinder at the leading edge of a lifting body can effectively control boundary layer separation. It is found that the upper limit on the angle of attack without separation is due to boundary layer accumulation on the wind tunnel walls and hence does not represent a limitation in applications. A predicition of the pressure distribution on the tested model is obtained by applying Smith's (1958) technique to the solution of the Newman problem. The gap between the cylinder and the fixed afterbody should be maintained at its minimum practical value in order to minimize the cylinder speed required for effective boundary layer control.