Numerical methods are used to study the growth of waves of finite amplitude on a pair of parallel infinite vortices. The vortices are treated as lines except in so far as the detailed structure of the core is needed to remove consistently the singularity in the line integrals for the velocities of the vortices. It is shown that the vortices eventually touch and the shape of the wave at this instant is calculated. The wave is quite distorted at this instant, but it is shown that its gross properties are given roughly by linear theory.

The buckling of simply-supported sandwich panels, made up from fibre reinforced laminated face plates and honeycomb cores, is considered when they are subjected to uniform end loading. Numerical results are given for both overall buckling and face plate wrinkling for panels having typical carbon fibre faces with the laminations arranged to give effectively orthotropic properties.

Measurements are presented of the base pressure coefficient, drag coefficient and Strouhal number of rectangular cylinders. The results confirm a finding in Japan that the drag coefficient rises to nearly 3 when the depth of the section is just over half the width. The flow around the sections is found to be strongly influenced by the presence of the trailing-edge corners.

The inviscid interaction resulting from the penetration of a jet of air into the throat region of a bounded mainstream flow is investigated analytically and experimentally. Taking into account the effects of jet shocks, a control volume analysis is used to calculate the mainstream and jet conditions at the boundaries of the interaction region. These results are then used to estimate the shape of the interface separating the jet and mainstream. Particular attention is given to the throttling of the mainstream flow and the analytical predictions show agreement with the experimental measurements.

The momentum analysis of the mean flow of an incompressible fluid in a straight suction duct with porous walls dealt with in a previous paper is extended to account for deflection of the inflow towards a direction parallel with the axis of the duct. Ducts with a continuous distribution of porosity and ducts with a relatively small number of rather large ports are considered and the results are applicable to regions where the velocity and pressure can be assumed to be distributed uniformly across planes normal to the mean flow inside them. Some measurements made with a one-quarter full-size scale model of the straight and more or less regularly obstructed suction duct used in the boundary layer control system of a high-lift research aircraft show that at least part of the theory permits a reasonable prediction of pressures.

In an earlier paper the lower bounds for the pressure jumps across the bow shock waves of a supersonic transport were derived, it being assumed that all the shocks had coalesced into either the bow or rear shocks, but not that the shocks were at such a great distance (asymptotic) that they had the same strength. In this paper the results of the earlier work are developed so that the lower bounds for the pressure jumps across shock waves propagating through a homogeneous atmosphere are determined by considering bow and rear shock waves simultaneously.

Solutions of equations governing the flow in the plane of symmetry of a corner boundary layer with favourable pressure gradients are presented. The results indicate that as the pressure gradient is reduced the secondary flow in the plane of symmetry reverses its direction from a flow into the corner to an outflow away from the corner, the main velocity profile being of the separation type with zero gradient at the wall and a point of inflection within the boundary layer. As the pressure gradient is reduced further the numerical method of solution is found to break down, possibly because of a drastic change of character in the family of solutions. This may be indicative of a corresponding change of character in the physical flow which, it is hoped, may clarify some of the unexplained phenomena disclosed by recent experiments on the corner boundary layer with zero pressure gradient.

Surface pressure measurements and schlieren photographs at M∞ = 2.50 and M∞ = 4.00 are presented for a family of axisymmetric elliptically-nosed models with cylindrical afterbodies. The results are an extension of those obtained by Holder and Chinneck on the same series of models at lower Mach numbers.

Some comparison is made with theoretical results, and the forebody surface pressures obtained experimentally are found to be in good agreement with results obtained using either the method of integral relations or the time-dependent method.

This paper determines the thickness variation in an annular strip (a curved beam) under pure bending to give a constant equivalent stress based on the Mises-Hencky yield criterion. The stresses due to an applied shear are also determined.