Experimental aeroacoustic study of noise reduction devices for UAVs

Abstract

The present study focuses on the effects of noise reduction devices for unmanned aerial vehicles, motivated by the sudden growth in the number of consumer and commercial drones, which could lead to an increase in noise pollution, especially in major cities. Initially, a summary of possible solutions to noise reduction is presented in the literature review section, then, the 3D printing and manufacturing process is explained for each device built. Thereafter, two duct and four propeller configurations are tested and analyzed through the signal acquisition of the noise frequency spectrum, which demonstrates that ducts amplify the noise signature in a range of high frequencies, while certain propeller configurations manage to reduce over 0.5 dBA for most of the frequency spectrum and up to 4 dBA at certain frequencies. Finally, results and conclusions are discussed in the final chapters, comparing the effectiveness of each device to the unshrouded standard propeller.