Improving propeller noise measurement and prediction by applying acoustic imaging

In recent years, there has been a rise of electric propeller aircraft in the field of general aviation. These propeller aircraft greatly reduce the emissions and engine noise compared to conventional aircraft, but noise coming from the propeller stays unchanged. Acoustic imaging, using beamforming, could help in the characterization of associated noise sources. In this research, the noise of a Cessna Skymaster 337F is recorded using a microphone array, and two beamforming algorithms are applied in the data analysis: conventional beamforming (CTDBF) and rotating beamforming (ROSI). The combination of these two algorithms adds a new dimension to acoustic analysis of propeller noise, namely a choice of reference frame, which allows the researcher to separate rotating noise sources from stationary noise sources. It has been shown that this is a very valuable tool for localizing the noise, making it easier to reduce the propeller noise in future research.Dutch Electric Aviation CenterAerospace Engineerin