The application of optical imaging techniques tohypersonic facilities is discussed and examples ofexperimental measurements are provided. TraditionalSchlieren and shadowgraph techniques still remain asinexpensive and easy to use flow visualisationtechniques. With the advent of faster cameras, thesemethods are becoming increasingly important fortime-resolved high-speed imaging. Interferometry’squantitative nature is regularly used to obtaindensity information about hypersonic flows. Recentdevelopments have seen an extension of the types offlows that can be imaged and the measurement ofother flow parameters such as ionisation level.Planar laser induced fluorescence has been used tovisualise complex flows and to measure suchquantities as temperature and velocity. Futuredirections for optical imaging are discussed.

This paper presents investigations oflow-Reynolds-number flows past an SD7003 aerofoil atRe = 60k, where transition takes place across alaminar separation bubble (LSB). Results ofexperimental measurements and numerical calculationsare analysed and discussed. In particular,reasonably good results were obtained using twodifferent numerical approaches: Large-eddysimulation (LES) that demonstrated vorticalstructures at different transition stages, and wherethe transition occurred naturally; unsteadyReynolds-averaged Navier-Stokes (URANS) simulationsfor several turbulence models based on theω-length-scale equation, coupled to a linearstability solver to predict the transitionposition.

When the stagnation temperature of a perfect gasincreases, the specific heats and their ratio do notremain constant and start to vary with thetemperature. The gas remains perfect; its stateequations remain valid, so it can be named ascalorifically imperfect gas. The aim of thisresearch is to develop the necessary thermodynamicand geometrical equations and to study thesupersonic flow at high temperature, lower than thedissociation threshold. The results are found by theresolution of nonlinear algebraic equations andintegration of complex analytical functions wherethe exact calculation is impossible. The dichotomymethod is used to solve the nonlinear equations andSimpson’s algorithm for the numerical integrationapplied. A condensation of the nodes is used. Thefunctions to be integrated have a high gradient atthe extremity of the interval of integration. Thecomparison is made with the calorifically perfectgas to determine the error. The application is madefor air in a supersonic nozzle.

Complex weather conditions, especially windshear andicing encounter, have severe effects on aircraftflight safety. The effect of low-altitude windshearand ice accretion on aircraft performance andcontrol has been studied in this paper. With theemployment of a windshear model and nonlinearinverse dynamics (NID) method, a low-altitudewindshear penetration flight control law isdesigned. The effect of ice accretion was modeled onthe stability and control of an aircraft. Severalicing parameters are imported to the smalldisturbance flight dynamics model to calculate thechange of performance, stability and controlderivatives between clean and iced aircraft. Thesederivatives were used to calculate the elevator, theaileron and the rudder step responses to investigatethe icing effect.

The simulation results indicate that the NID controllogic works effectively in the trajectory control ofthe aircraft during the penetration of windshear.The method used to study the effect of ice accretionon aircraft is valid and it can provide data forreal-time calculation for icing encounter.

The starting process in a supersonic nozzle isnumerically simulated. The Navier Stokes equations,in axisymmetric form, are solved using a higherorder spatial and temporal accurate scheme. Goodcomparisons between experimental and numericalvalues of various flow parameters form the basis offurther analysis. The insight of the startingprocess in the nozzle, namely, the movement ofprimary and secondary shocks and contactdiscontinuity, has been obtained through analysis ofvarious flow parameters. It has been observed thatthe inviscid phenomenon is more predominant in theflow development process. Parametric studies havebeen carried out to determine the effect of nozzledivergence angle on the starting process.