Owl-inspired leading-edge serrations for aerodynamic noise mitigation in drone propellers

This study examines the aeroacoustic characteristics of a large-scale baseline propeller and three bioinspired, leading-edge (LE) serrated propellers using large-eddy simulations in conjunction with the Ffowcs Williams–Hawkings acoustic analogy. The LE serrations, inspired by the wing morphology of owls, are designed to mitigate aerodynamic noise in propellers for multirotor unmanned aerial vehicles. The results show a noise reduction of up to 3 dB, with a minor aerodynamic penalty of 4–8% in the figure-of-merit. Flow field analysis reveals that the LE serrations disrupt the formation of large-scale LE vortices, alter vortex shedding dynamics, and reduce high-intensity velocity and pressure fluctuations near the blade tips, effectively lowering both broadband and tonal noise emissions. Among the serration designs tested, a moderate serration size provides the optimal trade-off between noise reduction and aerodynamic performance, highlighting the importance of geometric optimization. These findings suggest that owl-inspired LE serrations offer significant potential for quieter propulsion systems for a range of aerial platforms, including large-scale multirotor drones and emerging concepts such as flying cars.