Three computer programmes have been written for the stability analysis of both isotropic and orthotropic, multi-plate structures in compression. The bases of these programmes are the exact and approximate Finite Strip methods. A considerable number of results for a range of multi-plate structures fabricated from both carbon fibre reinforced (orthotropic) and aluminium (isotropic) materials are presented in graphical form. These graphs serve to illustrate not only the influence of material orthotropy on the buckling response, but also the possible savings in weight that may be achieved by employing orthotropic materials in place of conventional isotropic materials.

A flow-restriction gas-heater concept is presented. Basically the gas is heated in multiple compressions, with the help of a reciprocating free piston, and with high entropy production within the gas due to the presence of a flow-restricting orifice. The characteristics of such continuously-operating heaters are studied by means of a simple theoretical model, including a first-order estimate of the significant heat losses. The independent gasdynamic and geometrical parameters are varied over practicable ranges, and steady-state heating cycles are digitally computed. The numerical results indicate interesting applications for the heater when the heat losses can be controlled.

When the incompressible potential flow past a three-dimensional body is represented by source distributions on the body surface, these source distributions have singularities near an edge or corner, for example á trailing edge of a wing or the (unfaired) intersection of a body and a wing. The nature of these singularities is discussed. When assuming slow variations of the geometry in the main flow direction we can consider a two-dimensional problem in the cross-flow plane. Here the tangential velocities and source distributions are proportional to certain powers of the distance from the corner. For example at a convex right-angled corner these powers are − ⅓ in the asymmetric case (the bisector is a potential line) and ⅓ in the symmetric case (the bisector is a streamline) for both sources and tangential velocities. At a concave right-angled corner the corresponding values for the source distributions are ⅓ (asymmetric case) and − ⅓ (symmetric case) whereas they are 1 and 3 respectively for the tangential velocities.

The effects of contraction geometry on non-isotropic free-stream turbulence were investigated experimentally. Eight nozzles of circular cross-section, having different contour shapes and various non-dimensional lengths, were tested. The contraction ratio was 10:1. The results are compared with test data for isotropic turbulence and with a well-known linear theory. It is found that the variation of the lateral component of turbulent energy along the nozzles is similar to that with isotropic free-stream turbulence, whereas the behaviour of the longitudinal component is entirely different. The change of turbulence depends on local contraction ratio only.

This paper gives two improved tapered elements for vibration analysis derived using quintic polynomial displacement functions. The elements employ different nodal continuity conditions. Results are compared with those given by the basic cubic approximations and analytical solutions for various end conditions. The advantages of the new elements over the basic element are discussed.

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.

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.