Spherical Array Based Drone Noise Measurements and Modelling for Drone Noise Reduction via Propeller Phase Control

Drone noise is increasingly becoming an annoying problem as they are widely used in everyday applications. This paper investigates the problem of controlling farfield drone noise by manipulating relative phase of propellers. The methodology includes (i) measurement of the nearfield propeller noise using a specially designed open spherical array, (ii) development of extrapolation method to transform nearfield noise to a farfield target region, and (iii) simulation of farfield noise field with varying propeller relative phases. We further investigate the influence of drone configuration of phase controlled noise reduction for a farfield target region, and show that −6.8 dB noise reduction can be achieved at the blade passage frequencies. The analysis of residual noise shows the potential benefit of combining phase control with active noise control.