Investigation of wing installation effects on the sound field of a model jet engine

Abstract

Civil air traffic has been constantly growing over the past decades. Therefore, the noise emitted by aircraft became increasingly important to public perception, as noise pollution has numerously evidenced adverse effects on human health. Jet noise - one of different noise sources of an aircraft - has been successfully alleviated by new technological advances, such as serrated nozzle geometries. This thesis aims to enhance the knowledge of jet noise generation by assessing the experimental data of an aeroacoustic investigation of jet noise generated by a common turbofan engine. The effects of aerofoil and pylon presence as well as different nozzle and cowling configurations are elaborated at flow conditions resembling the ICAO noise reference measurement points by examining the Sound field of the jet via source directivity analysis. The findings agree well with theory: Wing installation increases the sound pressure level slightly for all test cases due to reflection events, while the flight stream lowers the sound emission noticeably by encasing the hot core jet flows.