Experimental Investigations on Aerodynamic and Psychoacoustic Characteristics of Loop-Type Propeller

Abstract

AbstractThis study proposes a low noise loop-type propeller that provides lift by loops rather than blades, aiming to reduce the noise sound pressure level (SPL) and improve sound quality. Noise data were acquired via a hover stand test in an anechoic chamber. We then made a comparison of the SPL and psychoacoustic metrics (loudness, sharpness, roughness, and fluctuation strength) of the DJI Phantom 3 propeller and the loop-type propeller using acoustic analysis. Furthermore, we discussed the tonal noise and broadband noise components of both propellers. The aerodynamic force and torque results show that the two propeller types provide very similar figure of merit values, while the DJI Phantom 3 propeller shows higher lift and torque coefficients. In terms of aeroacoustics, the loop-type propeller can reduce the noise SPL at different positions under 5400 rpm. With Fastl and Zwicker's psychoacoustic annoyance model, we predict and demonstrate that the loop-type propeller can improve a human's psychological response to the sound via higher-level broadband noise and lower-level tonal noise components.KeywordsAeroacousticsPsychoacousticLoop-type propellerNoise experiment