A laser doppler anemometer (LDA) was configured to provide simultaneous ID velocity readings from two separate points in the contracting flow regime upstream of 0·63 m diameter model propeller operating under high thrust conditions. Cross-correlations between the velocity signals were used to map the progress of turbulent eddy structures throughout the distortion, even within the highly oscillatory region close to the blades. These measurements were used to provide data on the strength and velocity of the eddies, as well as their average size and shape in two dimensions. The results show both elongation of the turbulent structures in the streamwise direction and distortion along their length, caused by the contracting flow and the high Reynolds stress. Linearised isotropic theory was used to predict the changes in the turbulent kinetic energies, and was found to be accurate for the longitudinal component only.

An experimental investigation has been performed into the free jet and wall jet characteristics of high pressure ratio coaxial jets operating with inverted velocity profiles and impinging onto a ground plane. Pitot-static probes have been used to record free jet properties at various distances from the jet exit plane, and wall jet properties of the impinging jets at various radial positions. Jet properties such as velocity decay and spreading rates were calculated and compared to published literature. Wall jet development was investigated and recorded. Inner and outer nozzle pressure ratio (NPR) were altered to give a range of jet exit conditions. The results obtained showed variations in the wall jet properties as jet exit conditions were altered, but wall jet self-similarity was found and varying either nozzle height above the ground plane or NPR did not alter this. Free jet data showed large variations in behaviour with changes in NPR. The inverted profile jets behaved similarly to annular jets, showing similar characteristics. Inner jet pressurisation was observed for inverted profile jets and also significant acceleration of the flow from the inner, lower NPR, jet when this was subcritical.

Two new techniques for estimating aircraft stability and control derivatives (parameters) from flight data using feed forward neural networks are proposed. Both techniques use motion variables and control inputs as the input file, while aerodynamic coefficients are presented as the output file for training a neural network. For the purpose of parameter estimation, the trained neural network is presented with a suitably modified input file, and the corresponding predicted output file of aerodynamic coefficients is obtained. Suitable interpretation and manipulation of such input-output files yields the estimated values of the parameters. The methods are validated first on the simulated flight data and then on real flight data obtained by digitising analogue data from a published report. Results are presented to show how the accuracy of the estimates is affected by the topology of the network, the number of iterations and the intensity of the measurement noise in simulated flight data. One of the significant features of the proposed methods is that they do not require guessing of a reasonable set of starting values of the parameters as a popular parameter estimator like the maximum likelihood method does.

The established control anticipation parameter longitudinal handling qualities criterion is based on the assumption that the short term dynamic response of the aeroplane is classical, or second-order-like. Modern fly-by-wire aircraft often have longitudinal short term dynamics which are not second-order-like and to which it is difficult to apply the criterion. This paper presents a proposed generic control anticipation parameter which is a modified version of the control anticipation parameter and which may be applicable to both unaugmented and augmented aircraft of all types. The appropriateness of the modified criterion was illustrated by designing a number of command and stability augmentation control laws, constrained to meet the criterion, for application to a medium weight fly-by-wire civil transport aircraft. The handling characteristics conferred by the control laws were assessed in a series of flight simulator trials, the results of which are briefly presented.

The aim of the work outlined in this paper is to compare three different variable cycle jet engine concepts for future SSTs. These engines are: the turbofan-turbojet, the mid-tandem fan engine and the double bypass engine. The comparison is carried out on the basis of unin-stalled and installed performance, handling and sizing issues.

This preliminary analysis compares SFC, size, variable geometry and cycle changes for each engine. The installed performance was estimated by calculating the air friction, the pre-entry and the afterbody drags, together with the wave drag due to the shock waves. A sizing calculation was carried out for the whole nacelle. The uninstalled and installed fuel bill, for two standard missions, is also estimated.

These preliminary results indicate that the turbofan-turbojet and the mid-tandem fan engines are quite similar in terms of general suitability. The mid-tandem fan appears to be an attractive proposition from the point of view of sizing, however, this comes with a small penalty in fuel consumption. The present double bypass engine was found to be the least attractive for the application, although the differences are small.

The flowfield characteristics of jets from plain and rectangular orifices with semi-circular cut-outs have been experimentally investigated for both sonic and underexpanded conditions. Detailed pitot pressure measurements revealed that the cut-outs had a strong influence on the emerging flowfield. The rectangular orifice with cut-outs at the minor axis ends showed more effective mixing with shorter core lengths and faster near field jet decay when compared with the plain rectangular and the rectangular orifice with cut-outs at the major axis ends. The general trend of variation of shock cell length with fully expanded Mach number was consistent with Tam's theory, but the shock cell length of orifice jets were less than that predicted by Tam.

Experiments have been conducted to investigate the flowfield associated with two co-rotating vortices which represent the idealised vortex system associated with a novel rotor blade tip planform. These vortices were generated by two rectangular NACA 0015 half wings positioned upstream of the working section of a low speed windtunnel. Hot-wire measurements were conducted downstream of the generators using X-wire probes to document the strength, position and size of the vortices. A numerical model was utilised to provide an accurate means of determining vortex strength, position and size. Finally, the model was successfully extended to consider the rotation of the vortex system.

This paper describes a facility for the acquisition of simultaneous high quality particle image velocimetry (PIV) and unsteady surface pressures with high spatial and temporal resolution. The facility, developed through a long-standing collaboration between the Department of Aerospace Engineering at Glasgow University and the Fluid Loading and Instrumentation Centre at Heriot-Watt University, is currently being used in collaborative projects and has the potential to provide a level of detail previously unattainable for CFD validation.

Results from both measurement techniques will be presented to demonstrate the range and potential of the two systems. In addition, the value of combining the two techniques will be demonstrated by results from a blade-vortex interaction experiment in which both methods were applied. Finally, future applications of the combined system will be discussed.

The non-equilibrium fluid mechanics and thermodynamics of two-phase vapour-droplet and gas-particle flow are considered. The formation of the droplets as well as their subsequent interaction with the vapour are discussed. Five topics have been given particular attention: (i) CFD application to unsteady condensation waves, (ii) CFD application to shock waves moving through a vapour-droplet mixture, (iii) a new theory of nucleation of water droplets in steam turbines based on Monte Carlo simulation (steam turbines are responsible for 80% of global electricity production and the presence of moisture significantly reduces the turbine efficiency costing £50m per annum in the UK alone), (iv) a unified theory for the interpretation of total pressure and total temperature in two-phase flows and, (v) a unified theory of particle transport in a turbulent flowfield.

This paper describes a detailed experimental investigation of turbulent heat transfer in a radially rotating tube with particular reference to its application to the design of cooled turbine rotor blades. The paper focuses on the strategy adopted, the description of the apparatus used, the method of data processing and a selection of measurements which illustrate the manner by which Coriolis force and centripetal buoyancy force interactively affect the local heat transfer along the leading and trailing edges of the tube.

As well as re-confirming the fact that Coriolis force and centripetal buoyancy have a significant influence on the forced convection mechanism present due to the through flow, a number of new experimentally-based observations are presented. An empirical correlation, which is physically consistent, has been developed which permits the interactive effect of Coriolis force and centripetal buoyancy on forced convection to be evaluated and quantified.

The work has been motivated by the need to understand the general effect of rotation on the performance of the internal cooling airways used in gas turbine rotor blades.

Simple straight and curved beams of unidirectional glass-epoxy were tested in fatigue to investigate failure under overall interlaminar tension and shear combined with local stresses at cut plies. Similar behaviour was observed as under static loading, with overall and local stresses interacting to cause delamination. When normalised, all the results lay close to, or above, a line determined from previous tension tests on specimens with cut plies, suggesting that this could be used as the basis for through thickness fatigue strength calculations.

Effective operation of a large-scale supersonic intermittent blow-down windtunnel system requires suitable control of the air control valve to establish the desired pressure profile in the settling chamber and generate a corresponding supersonic air flow. In this paper, we establish a lumped parameter nonlinear time-varying mathematical model for blowdown-type windtunnels, based on the thermal-fluid mechanical balance principle. We apply the LQG/LTR procedure to achieve a robust controller design that diminishes the effects of unavoidable uncertainties and time-varying characteristics and obtains the desired experimental environment in the system. Simulation results show that this LQG/LTR based controller, with a carefully selected loop shape combining both anti-integrator windup and the time-delay compensation schemes, achieves satisfactory control performance for the entire windtunnel testing procedure.

Measurements of drag have been made, in a shock tunnel, on a simple integrated vehicle-engine combination for hypersonic cruise with hydrogen scramjet propulsion. The test flow Mach number was 6·4, and the velocity was 2·45 kms-1. Zero drag, which is the necessary condition for cruise, was achieved as the equivalence ratio approached one. It was found that an analysis using established aerodynamic concepts was adequate for predicting drag in the case of no combustion. When combustion occurred results of direct connect experiments provided a qualitative guide to the measured levels of drag, and indicated that thrust nozzle combustion was taking place. An heuristic analysis is used to point to the important effect this may have on propulsive lift.

Reliable measurements of unsteady pressure on the surface of thin aerodynamic bodies in low subsonic, unsteady flows were made using small piezoelectric transducers. The hand-made transducers, calibrated against a B&K microphone for use in experiments, were used in two sets of low speed experiments. The first set involved a stationary aerofoil encountering a rotating, periodic gust as would be present in a rotor-stator interaction. The second set involved an instrumented propeller operating behind a stationary cyclic distortion as would be present behind stators or guide vanes. In both sets of experiments, reliable measurements of the small unsteady pressures on the body surfaces were made despite difficult experimental environments.