THE PREDICTION OF AIRFRAME NOISE AND COMPARISON WITH EXPERIMENT

The success of the high bypass ratio turbofan engine in reducing the external noise of civil transport aircraft at take-off and landing, while improving the economics of air travel, has opened up the debate as to how much further it will be possible to reduce aircraft noise by the introduction of new aircraft or existing aircraft retrofitted with new engines. Irrespective of what new technology can offer in respect of further engine noise reduction for no loss of performance, it is now clear that all future aircraft will require airframe noise to be reduced on the approach, since today it is comparable with engine noise. This paper discusses the major components of airframe noise and reviews the present state of airframe noise prediction. Finally, a comparison is made between prediction and experimental data and the prospects for airframe noise reduction.