Experiments are described in which the lift on a rectangular element of a two-dimensional wing and on a finite aspect ratio wing has been measured in grid turbulence. By measuring the spectrum of the lift and the spectrum of the turbulence upwash component, an experimental value for the turbulent admittance may be found. This is compared with a calculated value based upon linearised theory.

A theoretical and experimental investigation has been made into the effect of swirl on a supersonic jet. In certain circumstances a core of reversed flow can occur along the axis of symmetry and the jet mixes much more quickly with the ambient air than does the corresponding non-rotating jet. A characteristic calculation has been performed for the first cell in the case where the axial flow is not reversed. This indicates a shortening of the cell length and the formation of shocks nearer the nozzle.

Vandrey’s procedure, based on the method of singularities (ring vortices), for finding the pressure distribution on an axisymmetric body in a uniform stream is extended to the case of flow past a similar body in a uniform stream within a cylindrical duct of infinite length. The final form of the integral equation for the velocity distribution on the body is the same as that given by Vandrey; however, its kernel possesses additional terms representing the influence of the duct. Numerical solutions are worked out for varying radii ratio between a sphere and a duct and also between the more general-shaped axisymmetric body and a duct.

A study is made on the aerodynamic interference between a wing and a surface of velocity discontinuity in a non-uniform potential flow field. Actually, the surface of velocity discontinuity is deformed around the wing, which penetrates the surface, but no theoretical predictions of the surface deformation can be found in existing papers. In the present paper, a deformation of the surface is theoretically predicted, leading to the conclusion that a “sectorial region” will be formed on the wing. Formation of the sectorial region is recognised in new experiments and in many existing experimental results. Both theoretical and experimental analyses are made of the physical roles of the sectorial region.

The concept of a fully-developed flow based on the hypothesis of selective memory is here applied to general wall-jet type flows. In the presence of a (constant) external stream, the free-stream velocity and the jet momentum flux are taken to be the chief quantities governing the development of the wall jet: two additional non-dimensional parameters, representing a momentum flux Reynolds number and the relative momentum defect in the initial boundary layer, are shown to have only a secondary effect on the fully-developed flow. The standard correlations so determined are also found to predict quite well the flow development in Gartshore and Newman’s experiments on wall jets in adverse pressure gradients; possible reasons for this somewhat surprising result are discussed. Finally it is shown, by application to the still-air case, that the parameters discovered in incompressible flow are, with appropriate but straightforward modification, successful in describing compressible wall jets also.

Similar solutions of an equation governing the flow in the plane of symmetry of a corner boundary layer with favourable pressure gradient are extended to a “critical” value of the pressure gradient for which no solution could be found previously. It is shown that the failure to achieve this result in the past was due to the “singular” nature of this solution rather than to its non-existence as one was tempted to suspect. The existence and uniqueness of this crucial solution are demonstrated and the solution itself is obtained to a high degree of numerical accuracy. Criticism of the theory on which this corner boundary-layer equation is based is discussed in an Appendix.

The problem of a non-planar wing of finite span very close to the ground is considered by the method of matched asymptotic expansions. This method is based on the work of Widnall and Barrows, in which a planar wing very close to the ground was examined in detail. A simple analytic solution, to first-order approximation, is obtained for a non-planar wing which is uncambered. Expressions for the lift coefficient, induced angle and induced drag coefficient, which are valid for small ground clearance and moderately small aspect ratio, are derived for the case when the configuration of the wing projected onto a transverse plane normal to the free stream is elliptic. The problem of the optimum lift distribution around the wing and the rolling-moment coefficient for the inclined flat wing are discussed.

The distribution of camber and of aerofoil angle of attack is given analytically for an optimally loaded non-planar wing, to first-order approximation. Moreover, it is seen that, to first-order approximation, the aerodynamic forces given for the small aspect ratio are independent of the wing planform and depend only on the wing configuration at the trailing edge projected onto a transverse plane.