Graduate School of Engineering, Chiba University, Chiba 263-8522, Japan.
Central Research Institute of Electrical Power Industry, Abiko 270-1194, Japan.
Int J Environ Res Public Health. 2023 Jan 20;20(3):1955. doi: 10.3390/ijerph20031955.
Aeroacoustic noise in multiple rotor drones has been increasingly recognized as a crucial issue, while noise reduction is normally associated with a trade-off between aerodynamic performance and sound suppression as well as sound quality improvement. Here, we propose an integrated methodology to evaluate both aeroacoustics and psychoacoustics of a single propeller. For a loop-type propeller, an experimental investigation was conducted in association with its aerodynamic and acoustic characteristics via a hover stand test in an anechoic chamber; the psychoacoustic performance was then examined with psychoacoustic annoyance models to evaluate five psychoacoustic metrics comprising loudness, fluctuation strength, roughness, sharpness, and tonality. A comparison of the figure of merit (FM), the overall sound pressure level (OASPL) and psychoacoustic metrics was undertaken among a two-blade propeller, a four-blade propeller, the loop-type propeller, a wide chord loop-type propeller, and a DJI Phantom III propeller, indicating that the loop-type propeller enables a remarkable reduction in OASPL and a noticeable improvement in sound quality while achieving comparable aerodynamic performance. Furthermore, the psychoacoustic analysis demonstrates that the loop-type propeller can improve the psychological response to various noises in terms of the higher-level broadband and lower-level tonal noise components. It is thus verified that the integrated evaluation methodology of aeroacoustics and psychoacoustics can be a useful tool in the design of low-noise propellers in association with multirotor drones.
多旋翼无人机的空气动力噪声问题日益受到关注，而降低噪声通常需要在气动性能、噪声抑制和音质改善之间进行权衡。在这里，我们提出了一种综合方法来评估单个螺旋桨的空气动力噪声和心理声学特性。对于环型螺旋桨，通过在消声室内的悬停试验，对其空气动力和声学特性进行了实验研究；然后使用心理声学烦恼模型来评估五个心理声学指标（包括响度、波动强度、粗糙度、尖锐度和音调）来研究其心理声学性能。在两叶片螺旋桨、四叶片螺旋桨、环型螺旋桨、宽弦环型螺旋桨和 DJI Phantom III 螺旋桨之间，对优值（FM）、总声压级（OASPL）和心理声学指标进行了比较，结果表明，环型螺旋桨在实现相当的气动性能的同时，能够显著降低 OASPL 和显著改善音质。此外，心理声学分析表明，环型螺旋桨可以改善对各种噪声的心理反应，特别是对宽带和低水平的音调噪声成分。因此，验证了空气动力噪声和心理声学综合评估方法可以成为与多旋翼无人机相关的低噪声螺旋桨设计的有用工具。
