Several afterbody flows, involving shock-boundary-layer interaction, are used to evaluate recent developments in a realizable low-Reynolds-number, second-moment closure of turbulence. The model considered is a compressibility-adapted variant of the recent incompressible-flow form of Craft and Launder. This includes a tensorially cubic model for the influential pressure-strain process, ϕij, which satisfies the two-component-turbulence limit at the wall, is directly applicable to low-Reynolds-number flow regions and does not rely on or use surface-topography parameters, such as wall-normal distance or direction. Improved predictions for afterbody flows are demonstrated, relative to existing low-Reynolds-number two-equation models and the most elaborate form of Reynolds-stress closure incorporating a linear approximation for the pressure-strain process.

Handley Page Jetstream G-NFLC has for many years been used to complement the theoretical teaching material on undergraduate and postgraduate aeronautical engineering courses through a set of airborne laboratories designed to expose students to practical measurements in a realistic environment. It is suspected by some of the Cranfield test pilots that the aeroplane may be prone to pilot involved oscillations in pitch during the flare; the most likely causes are a deterioration in the short period dynamics at aft centre of gravity locations and adverse longitudinal stick force characteristics. To date however, no objective data has been available to support this hypothesis. This study reports upon an experiment designed to quantify these effects by identifying linear models of the short term dynamics from flight-test data, and assessing them against the Gibson drop-back and phase rate criteria. As expected, a rearward shift in the centre of gravity causes the airframe short period pitching oscillation (elevator deflection to pitch rate) to become more sluggish, thereby producing a significant reduction in dropback, which can be traced directly to the size of the static margin. The longitudinal stick force characteristics have a negative impact on the response, causing a reduction in dropback and a substantial increase in phase rate.

The goal of life extending control (LEC) is to enhance structural durability of complex mechanical systems, such as aircraft, spacecraft, and energy conversion devices, without incurring any significant loss of performance. This paper presents a concept of robust life-extending controller design for reusable rocket engines, similar to the Space Shuttle Main Engine (SSME), via damage mitigation in both fuel and oxidiser turbines while achieving the required performance for transient responses of the main combustion chamber pressure and the oxidant/fuel mixture ratio. The design procedure makes use of a combination of linear robust control synthesis and nonlinear optimisation techniques. Results of simulation experiments on the model of a reusable rocket engine are presented to this effect.

The discrete element method is modified so as to simulate the movement of passengers evacuating an aircraft. The results display reasonable agreement with timed trials. However, by focusing on the 1985 Manchester air disaster where only some of the exits could be opened and only then a considerable time after landing, it is argued that the certification procedures are inadequate.

Multidisciplinary design optimisation (MDO) provides a framework for the timely exchange of data necessary to support the highly integrated tasks typical of aerospace design. This will help reduce the duration of the design cycle and improve efficiency of the final product. Well implemented MDO capabilities will play an increasingly important role in DERA's activities to support the definition of future system requirements and the assessment of new equipment.

The framework in which an MDO approach is realised must be flexible and accommodate the diverse range of individual discipline-based tools that contribute to the overall process. This paper describes DERA's activity within the EC Framework IV ‘FRONTIER’ project to investigate the use of modern graphical user interface (GUI) methods and genetic algorithms (GAs) for the combined aerodynamic and structural design of a modern combat aircraft. The application of the techniques to identify a Pareto frontier in high level design objective space that represents the boundary beyond which improvements cannot be made without sacrificing one or other aspect of overall aircraft performance is described. The scope of the methods as an aid during the definition of system requirements and for the evaluation of trade-offs during the concept assessment stage of a project is discussed.

The operational requirements of modern combat aircraft demand complex engine intake and exhaust systems, capable of working efficiently over a very wide range of flight conditions and throttle settings. In addition to high aerodynamic efficiency and avoidance of high distortion levels at the engine face, these systems must also meet rigorous radar and infra-red signature targets. This paper discusses the implications from the aerodynamics point of view. Examples of technical approaches which seek to balance the sometimes conflicting requirements of aerodynamics and signatures are outlined. The potential offered by in-flight thrust vectoring to enhance flight performance and/or safety is also reviewed and the aerodynamic implications considered. Overall, propulsion integration for combat aircraft presents several challenges to the aerodynamicist, not least the development and validation of improved theoretical design methods capable of analysing the highly complex flows involved.