The paper develops and extends the calculation method of Stratford, for flows in which a Blasius type boundary layer reacts to a sharp unfavourable pressure gradient. Whereas even the more general of Stratford’s two formulae for predicting the position of boundary-layer separation is based primarily upon an interpolation between only three exact solutions of the boundary layer equations, the present proposals are based upon nine solutions covering a much wider range of conditions. Four of the solutions are for extremely sharp pressure gradients of the type studied by Stratford, and five are for more modest gradients. The method predicts the position of separation extremely accurately for each of these cases.

The method may also be used to predict the detailed distributions of skin friction, displacement thickness and momentum thickness, and does so both simply and accurately.

An approximate method is presented for estimating the normal-force and pitching-moment characteristics (including the effects of wing-body interference) of wings mounted on bodies. A pair of wings placed side by side can be specified which, when operating at a certain angle of attack different from the geometrical angle of attack, have the same aerodynamic properties as the wings in the presence of the body. The equivalent wings and effective angle of attack are determined, and these enable the wing-body normal force and pitching moment to be estimated for wing-body combinations at angles of attack up to 90°. Comparisons made with the results of a specially conducted series of experiments on rectangular and delta planform wing-body combinations have provided gratifying supporting evidence for the theory.

Estimates are also made of the normal force and pitching moment produced by two cone-cylinder bodies over the angle of attack range 0° to 90°. These estimates, when added to the wing-body normal-force and pitching-moment estimates, have resulted in a set of longitudinal aerodynamic characteristics which are generally close to those found experimentally. The method appears to have application in the preliminary design phase for slewing missiles.

Measurements of static pressure across the boundary layer on the wall of a circular cylinder with flow parallel to its axis display wall-interference effects which exceed corrections due to turbulence by almost an order of magnitude. Two different types of static pressure probe were investigated and gave different pressure distributions in the same boundary layer.

Results obtained by hot-wire measurements in a turbulent jet are presented for the cases where the jet issues into a co-flowing free stream and, for comparison, where the jet issues into quiescent air. The results obtained in the former show some agreement with other workers, but they are more extensive, including measurements of microscales and macroscales. The results also suggest that the presence of a free stream reduces the rate of decay of the longitudinal turbulent component of velocity, which has the effect of increasing the skewness of the eddy structure.

A free-vortex flow over a stationary disc produces a boundary layer on the surface which proceeds inwards towards the centre under the action of the imposed radial pressure gradient. Close to the centre the boundary layer leaves the surface to form a rising core. The present paper uses a control-volume approach and earlier calculations of laminar boundary-layer development on the disc to determine the characteristics of the core-formation process.

The method of Beecham and Titchener is extended to systems with n degrees of freedom and is shown to be a combination of the averaging principle and the method of variation of parameters. In this extended form, the method provides a powerful solution algorithm for non-linear problems such as those which arise in aircraft structural dynamics and aeroelasticity. The method is exemplified in application to a two-degree-of-freedom damped non-linear oscillator and to a binary (flexure-aileron) non-linear flutter system. The method is finally extended to non-linear differential equations in first-order form such as those which arise commonly in flight mechanics.