Master thesis and internship[BR]- Master's thesis : Experimental Procedure for Measuring the Noise Annoyance from Multi-Rotor Maneuvers using a UAV System[BR]- Integration Internship

Abstract

Nowadays, drone deliveries and urban air mobility are in conception and would arrive in our lives in the near future. These firsts are more often multi-rotor VTOL UAVs. This configuration is designed in order to operate in urban environments. The drones are likely to expose regularly to communities significant levels of noise. At the moment, no acoustic regulation exists to decrease the impact of disturbance in populated areas. However, the purpose of this research is to obtain a first understanding of the noise produced by a sUAV and on the impact on observers in the surroundings. Acoustic measurements of a sUAV multi-rotors have been performed in a free environment on the campus of the von Karman Institute for Fluid Dynamics. The recordings were conducted when the drone was hovering, flying over, tilting and in transition. The processing of the pressure data was focused on the power spectrum, the spectrogram and on three Sound Quality Metrics in order to give an evaluation of the noise annoyance.

The power spectra and the spectrograms reveal that for all maneuvers except the hover, the main BPF peak takes a larger range of frequencies and these lasts are varying because of the varying rotational speed of the front and rear propellers. Also, they show that over 3000 Hz, the tonal noise becomes hidden by the broadband one which becomes dominant.

Concerning the Sound Quality Metrics, they show that the overall Psychoacoustic Annoyance score is higher for the fly-over and transition maneuvers compared to the hovering flight. Therefore, the analysis with these different tools shows that the fly-over and the transition phase are the more annoying maneuvers for the human ear and have a greater impact on the community. However, the purpose of this research is to obtain a first understanding of the noise produced by a sUAV and on the impact on observers in the surroundings. Acoustic measurements of a sUAV multi-rotors have been performed in a free environment on the campus of the von Karman Institute for Fluid Dynamics. The recordings were conducted when the drone was hovering, flying over, tilting and in transition. The processing of the pressure data was focused on the power spectrum, the spectrogram and on three Sound Quality Metrics in order to give an evaluation of the noise annoyance.

The power spectra and the spectrograms reveal that for all maneuvers except the hover, the main BPF peak takes a larger range of frequencies and these lasts are varying because of the varying rotational speed of the front and rear propellers. Also they show that over 3000 Hz, the tonal noise becomes hidden by the broadband one which becomes dominant.

Concerning the Sound Quality Metrics, they show that the overall Psychoacoustic Annoyance score is higher for the fly-over and transition maneuvers compared to the hovering flight. Therefore, the analysis with these different tools shows that the fly-over and the transition phase are the more annoying maneuvers for the human ear and have a greater impact on the community.