A multivariate statistical analysis of the noise emitted by an installed propeller

Abstract Novel-aircraft concepts consider the possibility of placing propulsor very close to fuselage ingest incoming airframe boundary layer. In this configuration, engine takes inflow at a reduced velocity, consuming less fuel in combustion process. However, induces series noise consequences that alter tonal and broadband components. The present work reports an experimental investigation analyse sound emitted by propeller ingesting turbulent Experiments have been performed anechoic wind tunnel University Bristol set-up consisted two-bladed tangential flat plate simulate installed effects. A tripping device was placed 1 m upstream used generate layer location. velocity fixed 33 m/s keeping advance ratio J = 0.65. Far-field has acquired using microphone array positioned parallel plate, directly overhead propeller. data were analysed frequency domain, providing characterisation spectral quantities. Furthermore, wavelet analysis investigate time evolution identified pressure features. Results show evident haystacking humps higher BPF harmonics, due ingestion Moreover, revealed intermittent nature humps, clearly visible harmonics with low-frequency energy content.