Experimental and analytical investigation of contra-rotating multi-rotor UAV propeller noise
Experimental and analytical investigation of contra-rotating multi-rotor UAV propeller noise
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DOI：
10.1016/j.apacoust.2020.107850
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发表时间：
2021-01-22
影响因子：
3.4
通讯作者：
Jung, Riul
中科院分区：
文献类型：
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作者：
McKay, Ryan S.;Kingan, Michael J.;Jung, Riul
对转螺旋桨可以提高多旋翼无人机（UAV）的效率和提升能力;然而，对转螺旋桨会产生显著的噪声水平。在消声室中对静对转无人机螺旋桨噪声进行了实验研究。通过对1200和1500螺旋桨不同配置的试验，研究了螺旋桨直径的影响。还研究了螺旋桨间距、转速和叶片数量的影响;总共测试了大约1400个螺旋桨配置。据观察，相互作用的音调是一个占主导地位的贡献者的整体噪声水平，其中还包括转子单独的音调和宽带噪声。提出了对转螺旋桨产生的远场相互作用音调噪声的理论模型，并用于解释实验结果中观察到的音调噪声级。结果发现，音调与零方位角模式的顺序占主导地位的噪声频谱接近螺旋桨轴。结果表明，使用叶片数不匹配的对转螺旋桨，可以减少这些零阶方位模态音的振幅和数量。实验还表明，螺旋桨之间的间距增加通常会降低相互作用音调的幅度。振幅随螺旋桨间距的减小率取决于频率和间距。通常在小间距处观察到高衰减率，而在较大间距处观察到较低衰减率。然而，衰减既不是单调的，也不是在所有频率的均匀速率，这表明，有可能是一个变化的噪声产生机制的间距增加。最后，室内静态结果的有效性进行了证明，通过比较的结果与对转螺旋桨的四轴飞行器的飞行试验。(C)2020爱思唯尔有限公司保留所有权利。
Contra-rotating propellers could increase the efficiency and lifting capacity of multi-rotor unmanned aerial vehicles (UAVs); however, contra-rotating propellers can produce significant noise levels. This work experimentally investigated the noise from static contra-rotating UAV propellers in an anechoic chamber. The effects of propeller diameter were studied by testing different configurations of 1200 and 1500 propellers. The effects of propeller spacing, rotational speed and blade number were also investigated; around 1400 propeller configurations were tested in total. It was observed that interaction tones were a dominant contributor to the overall noise level, which also contained rotor-alone tones and broadband noise. A theoretical model for the far-field interaction tone noise produced by a contra-rotating propeller is presented and used to explain the tonal noise levels observed in the experimental results. It was found that the tones with a zero azimuthal mode order dominate the noise spectrum close to the propeller axis. It was shown that the amplitude and number of these tones with zero azimuthal mode order could be reduced by using contra-rotating propellers with mismatched blade numbers. It was also experimentally shown that increased spacing between the propellers generally reduced the amplitude of the interaction tones. The rate of this reduction in amplitude with spacing between the propellers was dependent on frequency and spacing. High rates of decay were generally observed at small spacings and lower rates at larger spacings. However, the decay was neither monotonic nor at a uniform rate for all frequencies, which suggests that there could be a change in the noise generation mechanism as the spacing increases. Finally, the validity of the indoor static results was demonstrated by comparing the results to an in-flight test of a quadcopter with contra-rotating propellers. (C) 2020 Elsevier Ltd. All rights reserved.