Boundary-layer interaction effects in intakes with particular reference to those designed for dual subsonic and supersonic performance

Abstract

The nature of flow in intakes with external boundary layer, at subsonic and supersonic speeds, is described. On the basis of a systematic series of wind-tunnel tests, a quantitative assessment is made of the loss or pressure recovery due to interaction between the boundary layer and the pre-entry pressure gradient, including the normal shock when present. The analysis leads to a formula which is suggested for general application. Boundary-layer Control to reduce or eliminate the interaction loss may require to take special form when it is necessary not only to safeguard the supersonic performance but also to minimise the subsonic drag. Some brief discussion of this problem is given.