The linearised time dependent momentum integral equation is used in conjunction with assumed velocity profiles and a quasi-static skin friction approximation to predict the turbulent boundary layer response to sinusoidal streamwise velocity fluctuations in the freestream. The mean zero pressure gradient case, corresponding to flat plate flow, is presented in detail and verified by comparison with experimental data and alternative calculations. The asymptotic turbulent boundary layer response to very high frequency perturbations is also derived. It is shown that a travelling wave component in the freestream, with its associated time dependent streamwise pressure gradient, has a dominant effect on the turbulent boundary layer response.

Simple, yet reasonably accurate, expressions have been developed for the prediction of skin friction and heat transfer coefficient at an infinite swept attachment line using the concepts of ‘reference temperature’ and ‘Reynolds analogy’. The formulae have then been used to investigate the effect of varying sweep angle with constant undisturbed free stream conditions in the limits of very low and very high Mach number.

A two parameter approximate solution is presented for the flow along a streamwise corner having large, possibly infinite, curvature in its region of transition between the two quarter infinite planes which form its asymptotes. The two parameters are the angle between the asymptotes and a quantity proportional to the ratio of the local two-dimensional boundary layer thickness and the radius of curvature of the corner at the symmetry plane. Relative to the corner of infinite curvature (sharp corner) a finite curvature always tends to modify the solution towards that for a flat plate. This implies that for corner angles less than 180° the corner layer thickness in the symmetry plane is less than that for the sharp corner of the same angle and the shear stress is higher, the converse holding for angles greater than 180°. The flow in planes normal to the free stream direction is rather complex and typically there is a reversal in its direction within the symmetry plane.

An analysis is made of the general two-cell thin-walled cylindrical tube subjected to longitudinal tension, bending and torsion. The walls of the tube may be of fibre composite with an asymmetric lay-up resulting in a coupling between direct and shear stresses and strains. The two-cell tube differs from the single-cell tube in that the tension axis and the principal axes of bending are not necessarily aligned to the c.g. and the principal moments of inertia of the longitudinal stress bearing material.

The subject of this paper is the effect of a disturbance to the turbulence structure of the flow on the reading of a Preston tube used to measure wall shear stress. Two kinds of disturbance have been studied experimentally, one caused by reattachment and the other by an abrupt change in wall roughness. The apparent wall shear stress measured by the Preston tube both in channel and boundary layer flows with these kinds of disturbance has been compared with the wall shear stress measured by a sublayer fence. The results give an idea of the magnitude of the error that is likely to arise when the Preston tube is used in a flow with disturbed turbulence structure.