Fan Noise Prediction and Control
Research includes exploring the level and frequency content of ‘buzz-saw' noise in the fan duct at take-off; the effect of absorbent linings; and broadband noise generated by a fan.
Jet noise and bleed valve noise
Current research aims to use new computational techniques and tools to relate aircraft engine exhaust noise to nozzle geometry, thus enabling engine designers to minimise aircraft noise at take-off.
Novel acoustic treatments for aircraft engine nacelles and bypass ducts
Ongoing activities relating to sources of noise in aircraft take-off and landing phases include: the development of computational acoustics tools to predict the absorption of noise by acoustic liners and far-field sound energy distribution; the effect of non-axisymmetric liners; and the integration of these methods into industrial-scale liner optimisation procedures.
Turbulence as a source of sound
Work on broadband noise using engineering models includes the development of theoretical and experimental techniques to characterise fan broadband noise and to distinguish between rotor and stator sources.
Computational methods and stochastic methods
Measurement techniques
Research into advanced acoustic measurement techniques involves both laboratory work and measurements on Rolls-Royce aircraft engines. Advanced microphone array techniques, such as polar correlation, automatic source breakdown and beamforming are applied to engines at outdoor test beds whilst inverse methods and de-reverberation techniques are used in indoor test beds. Duct acoustics and liner technology is studied in the ISVR/Rolls-Royce No-Flow rig which includes a multi-channel mode generator and in-duct and far-field microphone arrays.
Duct Acoustics
Research activities include analytical, semi-analytical and numerical methods to predict sound propagation and radiation in turbofan duct systems.
X-Noise
X-Noise is a European collaborative network of industrial, SMEs, university and research organizations working in the field of aircraft noise research. The Institute of Sound and Vibration Research is the X-Noise National Focal Point for the United Kingdom. The ISVR coordinates the UK X-Noise Network in Aeroacoustics.