An experimental verification of coles’ postulate of the Law of the Wake in three dimensions has been attempted. This hypothesis, which is strongly supported by experimental evidence in two dimensions, purports to represent the velocity vector in a yawed boundary layer by the sum of two vectors, whose magnitudes are found from the universal law of the wall, and a second universal function, the law of the wake. It has been found that the velocity vector can be represented in this way and the wake function required for this is very similar to Coles’ form. Limitations of the experimental arrangement however prohibited the comparison of vector directions with that proposed by Coles.

A spacetime formulation is presented to solve unsteady aerodynamic problems involving large deformation or topological change such as store separation, slat and flap deployment or spoiler deflection. This technique avoids complex CFD meshing methods, such as Chimera, by the use of a finite-volume approach both in space and time, and permits a locally varying real timestep. The use of a central-difference scheme in the time direction can yield non-physical transient solutions as a consequence of information travelling backwards in time. Therefore, an upwind formulation is provided and validated against one-dimensional and two-dimensional test cases. A hybrid formulation (central in space, upwind in time) is also given and unsteady cases are computed for a spoiler and spoiler/flap deployment, with all three formulations compared, demonstrating that the use of an upwind time stencil yields more representative physical solutions and improves the rate of convergence.

The satellite attitude control system (SACS) is a complicated system. In order to reflect the relationship among different components in SACS and analyse the impact of component faults on system performance, a complete simulation platform of the SACS based on Simulink is built in this paper. With the embedding of the specific reaction flywheel, gyroscope and earth sensor model, and the design of the controller based on the quaternion feedback, the simulation platform can not only simulate the real SACS at the component level, but it can also realise the injection of component faults for analysing the system performance. Simulations are conducted to verify the performance of the simulation platform. Simulation results show that this simulation platform has the ability to accurately reflect the control performance of the SACS, and the output accuracy of the component model is high. The research results reveal that this simulation platform can provide model support for verifying the algorithm of fault diagnosis, prediction and tolerant control of the SACS. This simulation platform is easy to use and can be expanded and improved.

Detached-eddy simulations for the 1303 UCAV geometry are undertaken aiming to investigate the flow physics of the interaction of a store with the flow inside a UCAV weapons bay. Advanced multi-block topologies had to be used to properly represent the planform of the UCAV and all the details of the weapon bay, including doors and hinges, while sliding meshes were needed to insert the store into the UCAV configuration. Results with an empty bay were encouraging for such complex configurations. Flow visualisation revealed the added turbulent content due to the door leading edges and hinges. The addition of a store in between the doors had little effect close to the front wall of the bay. However averaged flow-fields showed that the proximity of the shear layer to the apex of the store deflected it downwards into the bay and restricted its growth.

The object of this talk is to give you a situation report on the Concorde flight test programme and to indicate the progress made to date.

Two aircraft have been engaged on the programme so far, the prototypes 001 and 002 (Fig. 1). The French base for Concorde flight test operations is at Toulouse and the British flight test base is at Fairford in Gloucestershire. The two prototypes will be joined in the flight test programme next year by the two pre-production aircraft, 01 and 02.

As is well-known, Concorde is a slender delta wing aircraft and it may be appropriate at this stage to state some of the considerations that led to the choice of this configuration. By virtue of a large root chord, the delta wing can overcome all the disadvantages of lack of structural stiffness and lack of wing volume associated with thin highly swept wings and yet remain aerodynamically thin.

In a recent series of papers, Poll and Schumann have been developing a simple model for estimating fuel burn for turbofan powered, civil transport aircraft for a given mass, Mach number and flight level and in a specified ambient temperature profile for all phases of flight. This paper focuses upon the combination of Mach number and flight level at which an aircraft cruises with the absolute minimum fuel burn. For a given aircraft type, the information necessary to determine these conditions must be specified and this poses a challenge. An initial attempt to obtain these data has been described previously by the first author. In this paper, the optimum conditions are found using a completely different approach. Starting from first principles and using established theory, the equations governing the situation where engine overall efficiency and airframe lift-to-drag ratio both have local maxima at the same flight condition are developed. This special case is termed the “design optimum” condition and, for a specified aircraft mass and a specified atmospheric temperature versus pressure profile, it gives the lowest possible fuel burn for any aircraft and engine combination. The design optimum occurs at a particular Mach number and Reynolds number, and it is a fixed characteristic of the aircraft. The analysis reveals the significance of Reynolds number variations, wave drag, including its derivatives with respect to both lift coefficient and Mach number, and the atmospheric properties. Whilst wave drag is notoriously difficult to determine accurately, it is found that solutions to the equations are not particularly sensitive to the accuracy of this quantity. Consequently, a simple, physically realistic model can give good results. An appropriate model is developed and a complete, approximate solution is obtained. Taking the International Standard Atmosphere as the design atmosphere, results are presented for the 53 aircraft types previously considered by Poll and Schumann. Relative to the design optimum conditions, when Reynolds number is constant and wave drag is zero, compressibility alone reduces L/D by about 5%, reduces lift coefficient by about 1.5% and increases drag coefficient by about 3.5%. Reynolds number variation has little effect upon L/D, but it reduces lift coefficient and drag coefficient by a further 7% and 8% respectively. The reduction in lift coefficient has a significant impact on the optimum cruise flight level.

In general, an aircraft’s operating optimum will not coincide with its design optimum, but deviations are expected to be small. Therefore, using the design optimum solution as a reference point, an improved version of the operating optimum estimation method described by Poll and Schumann in previous work is developed. This allows the estimation of the conditions for absolute minimum fuel burn for an aircraft of given mass flying thorough any atmosphere. Updated coefficients for the 53 aircraft types are given.

A range of quasi-steady and unsteady aerodynamic models are used to predict the aerodynamic forces experienced by a flapping wing and a detailed comparison amongst these predictions in provided. The complexity of the models ranges from the analytical potential flow model to the computational Unsteady Vortex Lattice Method (UVLM), which allows one to describe the motion of the wake and account for its influence on the fluid loads. The novelty of this effort lies in a modification of the predicted forces as a generalisation of the leading edge suction analogy. This modification is introduced to account for the delayed stall mechanism due to leading edge flow separation. The model predictions are compared with two sets of independent experimental data and with computational fluid dynamics (CFD) simulation data available in the literature. It is found that both, the modified analytical model and the UVLM model can be used to describe the time history of the lift force, in some cases with better results than a high-fidelity CFD model. The models presented here constitute a useful basis for the aerodynamic design of bioinspired flapping-wings micro-air vehicles.