The minimum pressure drag of blunt forebodies in hypersonic flow is investigated using Newton’s Impact Theory. It is shown how the minimum drag shape varies with the body slenderness and the amount of blunting. As the blunting increases the drag approaches that of the minimum drag axisymmetric body.

This paper examines the performance of enriching the shape functions of interface finite elements in the prediction of mixed-mode delamination. Enriching second-order interface and solid elements with the analytical solution of a beam on elastic foundation problem yields the correct displacement field ahead of the crack tip. Despite the enrichment being fixed at elements nodes, resulting in non-traceability of the crack tip location, the strategy is shown to perform consistently well, increasing the minimum element size from the typical 0·5mm to 5mm, for a range of classical mixed-mode bending (MMB) specimens.

An experimental study of double cone geometries in hypersonic flow (at M∞ of 8·2 and Red of 0·36 × 106) was performed to provide additional data to a computational simulation study. In this study, depending on how the flow was initialised, the numerical solution yielded a violent pulsation mode of instability or a steady flow. Finally, an analysis of the shock oscillation was made and discussed.

This note assesses the benefits of active aeroelastic structures (AAS) in enhancing flight performance and control authority. A representative AAS concept, whose torsional stiffness and shear centre position can be altered depending on the instantaneous flight condition, is employed in the wing of a medium altitude long endurance (MALE) UAV. A multidisciplinary design optimisation (MDO) suite is used in this study. It turns out that AAS can be very effective when used for enhancing control authority of the vehicle but have limited benefits in terms of flight performance (lift to drag).

The engine/airframe integration design is one key differentiating factor for making efficient transport aircraft and this topic will become more important for future aircraft as the turbofan engine diameter is increased leading to a stronger engine-airframe interaction. Hopefully, the capabilities of advanced numerical simulations allow the involved complex phenomena to be taken into account and this is illustrated in this paper through several research studies: the use of the Reynolds averaged Navier-Stokes equations together with the drag extraction techniques to predict the drag, the simulation of unsteady complex interaction between the jet and the pylon with the zonal detached eddy simulation method, the pylon and nacelle design through multi disciplinary optimisation and the flow control technologies.

The present paper presents oil flow visualisations and pressure measurements over a hemisphere-cylinder body attached with a forward facing spike at Mach 6 and Reynolds number of 1·38 × 108 at 0° and 5° angle-of-attack. The oil flow pictures depict the separation region in the vicinity of the spike on the hemisphere-cylinder body. The oil flow visualisations will help to locate the reattachment shock wave on the hemisphere-cylinder body and also understand the flow field behavior on the blunt-nosed spike configuration. The pressure measurements over the hemisphere-cylinder body depend on the shape and the length of the spike. The pressure distributions over the blunt-nosed body show significant influence of the angle-of-attack. The maximum pressure coefficient on the hemisphere-cylinder body is a function of the spike length, shape of the aerodisk and angle-of-attack. The windward and leeward sides pressure variations show dependence of the geometrical parameters of the spike and shape of the spike. The hemisphere and the flat-faced aerodisk cause considerable reduction of pressure leading to decrease of aerodynamic drag compared to the conical spike.

Helicopters play a unique role in modern aviation providing a varied range of benefits to society and satisfying the need for fast mobility. However, environmental concerns associated with the operation of rotorcraft have increased due to envisaged growth of helicopter operations. New rotorcraft designs, innovative aero engines and all-electrical systems, which may take decades to be in service, are being developed in order to diminish rotorcraft footprint on environment. However, since there is a large number of polluting rotorcraft that are in use and will only gradually be replaced, in the near-term, improvements to minimise air quality degradation may also be possible from better use of existing rotorcraft by focusing on mission profile management. A multidisciplinary framework, intended to generate outputs for estimating rotorcraft block fuel burn and emissions, was developed. Outcomes generated with this tool were, subsequently, the basis to carry out a parametric study for assessment of light single-engine rotorcraft environmental impact, in terms of fuel burn and emissions. Single and multi-objective optimisation for minimum fuel consumption and air pollutant emissions was part of this research as well.