Modelling and mitigation of drone noise

According to studies by Airbus, one of the biggest concerns among the public regarding drones is the noise they produce. ICAO have also stated that when drones are flown “low and in great numbers” they will cause a significant level of noise. To date there is literature around the public’s perception of drone usage and noise, however there is currently no recommended software package for modelling drone noise. There has also been little work done into the level of noise that is likely to be emitted by drones used in the commercial market for tasks such as parcel delivery. This research aimed to investigate the noise emitted by drones and determine suitable operating conditions and flight paths to mitigate this noise. The research also aimed to investigate the suitability of the software package ‘iNoise’ for modelling noise emission by drones. The results showed noise emission can be mitigated by maintaining high altitudes and high speeds, as well as vertical take offs and landings. Although many of the noise levels recorded in this research for different flight conditions and flow numbers were lower than the maximum recommended LDEN for road traffic noise, they did approach this value at low speeds. As the sound power level used in this project came from a small quadcopter, it is reasonable to assume larger, commercial drones will have a higher sound power level, thus increasing the need for noise mitigation measures. The research also demonstrated the suitability of iNoise for modelling noise emissions caused by drone activity.