Mathematical Modelling and Computational Engineering Prediction of Turbomachinery Broadband Noise

The number of people wanting to fly increases year after year, leading to serious noise pollution on the ground. To solve this problem we need to better understand the sources of this noise inside the aircraft engines, and to be able to predict the noise while the engine is still being designed. This proposal is concerned with one of the biggest noise sources, which is the interaction between the wakes from the rotating fan and the downstream Outlet Guide Vanes (OGVs).Our key aim is to use a mixture of ideas from mathematical analysis and Computational Fluid Dynamics (CFD) to produce a CFD-based prediction method. Stages in this research will necessarily include: study of the distortion of turbulence shed from the fan by the intervening swirling flow, including comparison between mathematically-based models and large-scale computation; investigation of the noise generation by the interaction between these distorted eddies and the OGVs; and the propagation of the resulting noise upstream and downstream in the machine. We will work closely with the UK's leading aeroengine manufacturer, Rolls-Royce, and in particular much use will be made of the Companies' main computer code. We aim to produce an accurate prediction method and physical insight, which can later be applied in engine design.