A three-dimensional unsteady Navier-Stokes solver has been used to simulate stall inception in a single row ten passage segment of a transonic fan, the NASA rotor-67. At subsonic flow conditions, the 3D results illustrate a rotating stall inception with short scale part-span cells rotating at around 80% rotor speed, similar to that observed in some low speed experiments. However, at a supersonic relative inflow condition, the results show that an isolated blade row tends to stall in a one-dimensional breakdown pattern without first experiencing rotating stall. At near-stall conditions, significant self-excited unsteadiness is generated by the interaction between the tip-leakage vortex and the passage shock wave. Further computations for two-dimensional configurations indicate that it is possible to have a rotating pattern of instability in transonic blade rows associated with circumferential synchronised shock oscillation.

Non-destructive evaluation (NDE) technologies are a critical component of a collaborative engineering environment. The role of NDE simulations in component design, manufacturing, certification, integrity and repair are identified and discussed in the context of a futuristic intelligent synthesis environment (ISE) that facilitates collaborative engineering. Each of these critical areas needs to be simulated in a virtual reality environment and is expected to have a large effect on the cost, life, safety, and risk of aerospace products. In a collaborative engineering environment, NDE simulations will provide ‘real-time’ feedback to component designers and systems engineers. This feedback is necessary to achieve optimum overall system-level benefits.

The effects of the model surface to free stream adiabatic temperature ratio (Tw/Tad) on periodic transonic flow over a 14% thick biconvex aerofoil are evaluated using a computational fluid dynamic approach. The analysis is based on the thin layer Navier Stokes equations with Baldwin-Lomax turbulence model. The results of computations showed that on biconves aerofoils there is a large effect of heat transfer on instantaneous pressure distributions and periodic buffet excitation level confirming some of the available experimental data. The effects observed have an implication in wind tunnel measurement of buffet associated periodic transonic flows.

An experimental investigation was undertaken to determine the effectiveness of distributed surface porosity for the alleviation of pitch-up on a delta wing. Tests were undertaken using a 65° sweep delta wing with distributed porosity evaluated at various locations on the wing. Force balance, on and off surface flow visualisation and flow field surveys using a multi-hole probe were undertaken. The data shows that distributed porosity applied along the wing leading edge at the apex is effective in eliminating pitch-up whilst incurring a minimal performance cost. Trailing edge porosity generally degraded performance.

This paper describes and presents results from static wind tunnel tests conducted on a 60° delta wing at a root chord Reynolds number of 2·7 x 106. In these tests, the wing was instrumented with 192 miniature pressure transducers which, in conjunction with a powerful multi-channel data-logging system, allowed the distribution of time-varying surface pressures to be measured at high temporal resolution. Analysis indicates that the distribution of root mean square pressure on the leeward surface of the wing can provide considerable insight into the behaviour of both the primary and secondary vortex structures. In addition, it has been established that the frequency content of pressure signals measured in the vicinity of these vortex structures is sensitive to the vortex state. It is suggested that these data features can be directly attributed to previously observed behavioral characteristics of the vortex breakdown process.