Stochastic Methods For Computational Aero-Acoustics

The aim of the research programme is to develop a new class of numericalmethods for the solution of stochastic aeroacoustic problems. The random natureof many aeroacoustic problems stems from the presence of turbulent flows whichact as noise sources and also as an uncertain medium through which soundpropagates. The challenge is to devise numerical methods which preserve in somesense the uncertainty of the sound field and still represent accurately thecomplex physics of sound propagation through non-uniform flows. The projectwill focus on solutions of two aeroacoustic problems of urgent practicalinterest: (1) broadband fan noise where fan blades interact with their boundarylayers or turbulent wakes, (2) turbulent scattering by jet mixing layers wherethe unsteady random velocity field of a turbulent flow distribute the originalfrequency content of the source of sound. There is currently no generalsimulation methods available for these two applications and stochastic methodsrepresent a novel approach to the prediction of these sources of sound.Stochastic methods will be developed specifically for aeroacoustic applicationsand will draw on existing methods from other fields of engineering. After areview of the literature a selection of stochastic numerical methods will beimplemented and tested against benchmark problems. The accuracy andcomputational costs of the numerical schemes will be compared. Their ability tosolve large-scale realistic problems will be assess by considering anindustrial application. The proposed project will increase the range ofapplications that can be treated by computational aeroacoustics and willcontribute to the reduction of transport noise and especially aircraft noise.