The integral equation approach to the mixed flow problem of infinite wings at high subsonic speeds is adopted for non-circulatory and circulatory (lifting) flows. The solutions are determined from a system of non-linear algebraic equations and, to ensure always unique solutions, the method of differentiation with respect to a parameter has been applied. The resulting Cauchy problem is then solved with the linearised flow solution as the initial value vector. For the case of embedded shocks in the flow field, the method of steepest descent has been added to the calculation scheme. Results for subcritical and supercritical flows past aerofoils are given and compared with solutions obtained by finite-difference techniques.

The paper presents an experimental study of vortex systems generated in the region where an incompressible flow with spanwise varying velocity moves about a circular cylinder connected to a flat plate. The role that the various flow and geometric parameters play in the generation of the horseshoe vortex at the front of the cylinder is discussed and the dimensionless similarity numbers which describe the flow are derived.

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.

Experiments to determine the overall buckling and faceplate wrinkling loads of sandwich panels with carbon fibre reinforced plastic faces and honeycomb cores when loaded under uniaxial compression are described. The results are compared with theoretical predictions which assume that the faceplates are orthotropic. The effect on the experimental loads of certain coupling terms, which occur in the constitutive equations of those faceplates which are not orthotropic, is then considered.

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.

The linear, second-order, ordinary differential equations governing the free-vibration characteristics, in vacuo, of discretised systems executing, at equilibrium, steady rotational motion about a fixed point may be expressed in the well-known matrix-vector form involving real symmetric and skew-symmetric coefficient matrices. Less well known is the fact that the corresponding Hamiltonian first-order system may be cast into a special form involving a skew-symmetric system matrix. In this paper the computational merits of this special form are exploited in the calculation of the natural frequencies and modes of the rotating system.

It is shown that, if the well-known mixing-length formula is regarded simply as a relationship between the velocity and the stress distributions in the wall region of a turbulent flow, then a truly universal distribution of mixing length is sufficient to describe the experimentally observed departures of the velocity distribution from the usual law of the wall as a result of severe pressure gradients and transverse surface curvature. Comparisons have been made with a wide variety of experimental data to demonstrate the general validity of the mixing-length model in describing the flow close to a smooth wall.

An extension of the re-laminarisation criterion of Patel and Head, and some experimental evidence, suggest that the thick axisymmetric boundary layer on a slender cylinder placed axially in a uniform stream cannot be maintained in a fully turbulent state for values of the Reynolds number, based on friction velocity and cylinder radius, below a certain critical value.

From Kármán’s similarity hypothesis, we derive the equation which describes the mixing length in terms of the turbulent shear stress. For a boundary layer with linear stress distribution, the equation is in reasonable agreement with Bradshaw’s measurements. For a boundary layer with injection, it is shown that injection has an appreciable effect upon the mixing length when (vw/2) /(τ/ρ)1/2 becomes comparable to the Kármán constant. Close similarity is also pointed out between the hypotheses due to Kármán and Townsend. Moreover, the diffusion constant in Townsend’s hypothesis is determined to be 0.25, which is in good agreement with the value 0.2 obtained by Townsend from one experiment.

The results of measurements in laminar flow along a straight 135° corner are presented. Near to the inlet edge plane the flow has an appearance resembling that reported by Zamir and Young for a 90° corner in which the isovels in transverse planes are concave outwards near the bisecting line of the corner, but unlike the 90° corner flow this characteristic diminishes with distance downstream in the case examined here. The analytical solution by Carrier is found to be a good representation of the flow in the 135° corner.