Numerical Study of Noise Reduction on Looped Propeller Blades with Bio-inspired Tubercles

This paper investigates the effect of looped propeller blades with bio-inspired sinusoidal

leading-edge tubercles on the tonal noise generated. CFD simulations are conducted

using ANSYS Fluent, utilising a Detached Eddy Simulation flow model combined with a

Ffowcs Williams Hawkings model for acoustics. Further RANS simulations were conducted

for performance simulations in static and forward flight conditions. The findings show that

the baseline looped propeller was able to reduce tonal noise emitted from the propeller, by

up to 3.49dB at the blade passing frequency. It is also found that all the tested tubercle variations

on the looped design can further reduce the tonal noise by 0.98dB at the blade passing

frequency. The results further show that the looped propellers and their tubercle variations

reduced the maximum thrust generated but were able to reduce the input power required at

all tested velocities. This study’s findings demonstrate the potential of bio-inspired looped

propellers for eVTOLs and UAVs operating in urban environments.