The development of a new calculation method for compressible 3D boundary layers is described. The method involves a finite-difference discretisation of the governing mean-flow equations. In particular, the differencing scheme used to discretise spanwise derivatives adapts automatically to the sign of the local crossflow within the boundary layer. A plane-by-plane solution procedure in the spanwise direction enables second-order accuracy to be maintained throughout the whole flowfield. A normal coordinate scaling with the local total momentum thickness removes most of the boundary layer growth in computational space. The Cebeci-Smith algebraic turbulence model is used for the initial validation of the calculation method. A simple modification to this model is tested, involving an explicit dependence of the outer eddy viscosity on the crossflow within the boundary layer. There results a significantly improved prediction of the NLR infinite swept wing flow experiment.

This paper presents a method for assessing two-dimensional aerofoil lift and pitching moment characteristics including trailing edge and gross laminar separation. The model used is a direct viscid-inviscid interaction scheme based on a vortex panel method with boundary-layer corrections and an inviscidly modelled wake. The integral boundary-layer methods adopted behave well in the region of separation and thus, good comparisons with measured separation characteristics are obtained. Generally the predictions of lift and pitching moment may be considered to be within the experimental error, but where this is not the case, the applicability of the modelling technique is discussed.

The problem of fracture characterisation of geometrically complex structures is considered. Numerical and experimental strategies are used to evaluate stress intensity factors and elastic fields for cracked thin shell and plate structures. Theoretical analyses, using different order theories, are also performed in order to evaluate stress and energy distributions in the neighbourhood of the crack tip. A geometrically complex strut component is analysed by using a ‘p-convergent’ finite element code based on hierarchic elements and on the high degree of approximating functions. Actual fracture modes, for different crack locations, have been singled out and the elastic fields are compared to those referring to cracked plate and shell structures. An experimental investigation, using the optical method of caustics, has been also performed and stress intensity factors for several crack configurations have been calculated. The numerical investigations have shown the ability of the p-version finite element method to provide accurate computation of local stress values and to quote the convergence of the numerical calculations. The caustics method has confirmed its accuracy for evaluating stress intensity factors, even for complex structures.