A brief description is given of an accurate numerical method for the inverse calculation of both attached and separated laminar, two-dimensional, incompressible boundary-layers with prescribed displacement thickness. The method employs downstream-marching, using an approximation to the convection terms in the reverse-flow region to stabilise the computation. Results of three calculations made by this method, using measured distributions of displacement thickness as input, are presented and compared with the corresponding measured velocity profiles and distributions of external velocity. Very close agreement between theory and experiment is found in general, giving further evidence of the validity of the boundary-layer approximation in separated flows of limited extent.

This note presents the results of an experimental investigation of the flow over a simple delta wing designed for a Mach number of 3.5. Complete pressure distributions were measured for incidences of 0°, 10° and 20° at Mach numbers of 2.5 and 3.5. A number of schlieren photographs of the shock system around the wing were obtained at the same conditions and surface streamline patterns were studied at M = 3.5. The measurements were made to support numerical calculations which use this wing as a test case.

A method is described for calculating numerically the aerodynamic stiffness and damping coefficients and loading distributions for a two-dimensional thin aerofoil oscillating harmonically in subsonic flow, from the Possio Integral Equation by approximating the loading by a finite series of basis functions. Sample loading distributions obtained by using the method are presented for a Mach number of 0.9 and a frequency parameter of 0.4.

The singular behaviour of an incompressible boundary layer at separation has been well established by the works of Howarth (1938), Goldstein (1948), Stewartson (1958), Curie (1958) and Terrill (1960). Stewartson (1962) remarked that the existence of the singularity at separation can be regarded as fully established and understood. The skin friction vanishes like where x is the distance to separation, and the stream function close to the wall is described by a series of powers of , with coefficients that are functions of , where y measures distance normal to the wall. At some stages in the expansion of the stream function, terms in log x have to be included. The case of the compressible flow is less satisfactory. Stewartson (1962) was unable to establish singularity at separation and concluded that the general compressible boundary layer cannot have a singularity at separation unless there is no heat transfer from the wall. This has been contradicted by the works of Merkin (1968) and Buckmaster (1970). Curie (1958) also reported that the difficulty encountered in computing the temperature field right down to the point of separation might be due to the singularity there. In this paper, the Goldstein-Stewart son approach is applied to laminar boundary layer flow at low speeds in which density is sensibly constant and the Prandtl number σ is taken as unity. Singularity is established at separation for the temperature field. The heat transfer does not vanish at separation point and is of the form

The Nonlinear Magnus effect on the nutational oscillations of a missile has been studied. In particular the existence of self-sustained vibrations has been proved. A numerical method is suggested to obtain the limit cycles wherever they exist.

Incompressible flow perpendicular to a flexible, impervious membrane has been studied for two-dimensional conditions. The membrane was mounted on relatively thin supports spaced c apart. Measurements of drag, base pressure and the frequency of membrane oscillation are presented for various lengths ℓ, and for two densities, of membrane. These parameters are related to one another theoretically and in particular Bearman′s universal correlation for Strouhal number agrees with the experimental results. It is found that for values of < 0.50 the drag is independent of membrane density. The drag decreases at larger values of and this is related to a periodic reattachment of the separated flow to the back of the membrane. For a given ℓ the drag is greatest when is very small and the membrane is almost flat.