As part of a general investigation into Coanda effect, a study has been made of the reattachment of a two-dimensional, incompressible, turbulent jet to an adjacent, inclined, flat plate. The jet separates from the boundaries at the slot lips and reattaches to the plate downstream, a phenomenon which is associated with the lowering of the pressure between the jet and the plate accompanying the entrainment of fluid there. It is found that the flow becomes independent of both the length of the plate and the Reynolds number when these parameters are sufficiently large: the flow, scaled with respect to the width of the slot, is then uniquely determined by the plate inclination. Two approximate theories are developed for the mean pressure within the separation bubble, the position of reattachment and the increase in volume flow from the slot: the agreement with experiment is fairly satisfactory. These theories are a development of Dodds's analysis for the reattachment of a jet to a plate offset from, and parallel to, the axis of the slot and, for the purpose of comparison, a limited study is also made of this flow.

Equations are derived which enable the stresses around a compactly reinforced hole in an infinite sheet to be computed. The only restrictions placed on the shape of the hole are that it has at least one axis of symmetry and that the region outside it can be conformally mapped on to the region outside the unit circle by a transformation function in the form of a polynomial of any order. This admits a very wide range of holes of practical importance, including circles, ellipses, and squares, triangles and rectangles with rounded corners. Two loading cases are treated; the first corresponds to uniform tensions at infinity in directions parallel and perpendicular to the axis of symmetry of the hole, and the second to uniform shear at infinity in these directions. Superposition of these basic loading cases enables the stresses to be determined for any uniform state of stress at infinity. The equations are in an ideal form for use with a digital computer.

Recent free flight tests have provided information on the applicability of the sonic area rule to non-lifting configurations. An analysis of results for the sonic wave drag of swept-back, tapered wings has suggested that the sonic area rule is applicable to thin wing and slender body combinations provided that the product of the wing span/length ratio and the cube root of the thickness /chord ratio is less than unity. The wing span/length ratio was found to be a much more useful slenderness parameter than the aspect ratio.

When the wing has a round-nosed section, theoretical considerations predict the existence of a so-called leading edge drag force varying with Mach number. One would expect such a wing to have the same sonic drag-rise as the equivalent body with an identical cross-sectional area distribution. Some test results do not confirm this drag-rise equivalence. It appears that the transonic drag-rise of the leading edge force is much greater than that predicted by theory.

Tests on one basic wing-body combination, with different body cross-sectional shapes of the same area, suggest that the cross-sectional shape, of a smooth slender body, has no influence on the transonic wave drag of a configuration.

The analysis of the stability of second-order non-linear systems by Poincare's method of singular points in the phase plane is briefly presented and used to determine stability criteria for the short-period motion of an airframe having non-linear normal force and pitching moment curves. These results are then compared with those obtained by the application of quasilinear stability theory.

A set of design charts is presented for the calculation of transient temperature and thermal stress distributions in thermally thick plates subjected to aerodynamic heating.

The method is particularly useful for determining temperatures and thermal stresses in plates with an arbitrary variation of the heat transfer coefficient and the adiabatic wall temperature of the boundary layer. The present method is based on repetitive applications of the exact analytical solution to a unit triangular variation of the adiabatic wall temperature and a constant heat transfer coefficient. The actual variation of the adiabatic wall temperature is represented as a series of straight lines while the heat transfer coefficient is approximated by a step function. The temperature distribution through the plate is separated into linear and “self-equilibrating” temperature distributions to facilitate thermal stress calculations; these distributions can be obtained directly from the design charts presented in this paper.

The general principle of this semi-numerical method is also applied to thermally thin plates subjected to arbitrary heating conditions.

This paper discusses some of the special problems of wind-tunnel testing which arise with high-lift jet-blowing models, supplementing earlier comments. Further detailed remarks are made about recent developments on tunnel-wall interference, test rigs and methods of minimising constraints from air-feeds to models, and on general test and model design techniques.