Boundary Layer Control

Abstract

It has almost become a tradition in recent years to begin a paper on boundary layer by paying a tribute to the great Prandtl and his famous paper in which he introduced the conception of boundary layer into Fluid Dynamics.The year 1954 is, however, not only memorable to mark the passing of fifty years since Prandtl's classical demonstration of the effect of boundary layer suction on the flow pattern around a cylinder; it is also memorable because in 1954 most convincing demonstrations of practical applications of boundary layer control for aircraft have taken place. I am referring, in particular, to the demonstrations with the Attinello flap in the United States which mark the introduction of one form of boundary layer control as an engineering and practical reality.

Flow Control Using Moving Surface at the Leading Edge of Aerofoil

“…The whole assembly is shown in Fig. 1 The experiments were carried out in an open loop wind tunnel having test section of 0.30 X 0.30 X 0.60 m 3 . A wind tunnel model of NACA 0018 aerofoil having chord length of 0.15m with grooved leading edge was used to accommodate the rotating cylinder there.…”

“…are some of the ways of increasing the performance of aerofoil 1 . Out of these methods, efforts on boundary layer suction, boundary layer blowing, and vortex generator are found in various literatures [2][3][4][5][6] . But less effort was made on investigating the influence of momentum injection on the performance of aerofoil.…”

Conceptual Design for a Laminar Flying Wing Aircraft

“…The change of boundary layer thickness and velocity profile due to suction is detailed schematically by Lachmann (1955) in Fig. 2.2.…”

The broad delta airliner

“…9) with its rather large winglets. From his extensive review of LFC (6) in 1955, he concluded that low sweep back angles should be avoided and that pronounced sweep back angles of the order of 60° to 70° combined with very low thickness chord ratios were likely to achieve best results.…”