Speaker
Description
The spreading use of small UAVs makes their noise emissions a compelling issue for their social acceptance and public health impact. In this context, understanding the mechanisms of noise generation and identifying effective strategies for noise mitigation could favour a sustainable integration of UAVs into populated environments. To this aim, a parametric experimental study was conducted on a set of commercial off-the-shelf 5-inch UAV propellers. The study systematically examined the influence of design parameters such as blade pitch, number of blades, and blade geometry on the acoustic emission across different rotational regimes. The propellers were tested in single configuration as well as installed on a quadcopter. A comparison with recently introduced toroidal propellers was made to evaluate whether this unconventional geometry provides tangible benefits in terms of noise reduction without compromising thrust generation. Simultaneous measurements using a hot wire anemometer and microphones located in the nearfield and the farfield with respect to the source enabled the correlation of acoustic emissions with the underlying flow structures and unsteady phenomena responsible for sound generation.The results provide insight into the aeroacoustic performance of these systems, offering guidance for the development of quieter UAVs.