Paper:
Effect of Bio-Inspired Cutout Shapes at the Leading Edge of Propellers on Noise and Flight Efficiency
Ryusuke Noda*1 , Masaki Hirose*2, Teruaki Ikeda*3, Toshiyuki Nakata*4 , and Hao Liu*4
*1Department of Mechanical Engineering, Tokyo University of Technology
1404-1 Katakuramachi, Hachioji, Tokyo 192-0982, Japan
*2Department of Mechanical Engineering, Chiba University
1-33 Yayoi-cho, Inage-ku, Chiba, Chiba 263-8522, Japan
*3Fundamental Research Section, Advanced Technology Department, Teral Inc.
230 Moriwake, Miyuki-cho, Fukuyama, Hiroshima 720-0003, Japan
*4Graduate School of Engineering, Chiba University
1-33 Yayoi-cho, Inage-ku, Chiba, Chiba 263-8522, Japan
In recent years, the application of bio-inspired structures has garnered attention for enhancing the performance of fluid machinery. In this study, we experimentally investigated the effects of introducing a bio-inspired cutout structure to the propellers of drones, aiming to improve thrust efficiency and reduce noise levels. Our results demonstrated reductions in noise levels compared to conventional propellers. Parametric studies revealed that the roundness of the structure significantly influenced both flight efficiency and noise levels, suggesting its importance for replicating the inherent fluid characteristics found in nature. Additionally, optimal parameters for noise reduction, such as the length of the cutout, angle of incision relative to the flow direction, and the distance between the gap were identified. Although no improvements in flight efficiency were observed, most of the models investigated exhibited only around a 5% reduction in efficiency compared to the standard propellers, suggesting practical applicability for scenarios such as nighttime drone operations in urban areas. The noteworthy reduction in sound pressure levels in the mid- to high-frequency range achieved by the bio-inspired propellers in this study holds the potential to address the issue of drone noise pollution and encourage drone operations in urban areas. Moreover, the confirmed decrease in sound pressure at specific frequencies and the suggested controllability hint at the possibility of enhancing sound source localization performance using drones.
- [1] K. Nonami, “Drone technology, cutting-edge drone business, and future prospects,” J. Robot. Mechatron., Vol.28, No.3, pp. 262-272, 2016. https://doi.org/10.20965/jrm.2016.p0262
- [2] T. Benarbia and K. Kyamakya, “A literature review of drone-based package delivery logistics systems and their implementation feasibility,” Sustainability, Vol.14, No.1, Article No.360, 2021. https://doi.org/10.3390/su14010360
- [3] D. Y. Gwak, D. Han, and S. Lee, “Sound quality factors influencing annoyance from hovering UAV,” J. of Sound and Vibration, Vol.489, Article No.115651, 2020. https://doi.org/10.1016/j.jsv.2020.115651
- [4] B. Schäffer, R. Pieren, K. Heutschi, J. M. Wunderli, and S. Becker, “Drone noise emission characteristics and noise effects on humans—A systematic review,” Int. J. of Environmental Research and Public Health, Vol.18, No.11, Article No.5940, 2021. https://doi.org/10.3390/ijerph18115940
- [5] H. Bian, Q. Tan, S. Zhong, and X. Zhang, “Assessment of UAM and drone noise impact on the environment based on virtual flights,” Aerospace Science and Technology, Vol.118, Article No.106996, 2021. https://doi.org/10.1016/j.ast.2021.106996
- [6] C. Ramos-Romero, N. Green, S. Roberts, C. Clark, and A. J. Torija, “Requirements for drone operations to minimise community noise impact,” Int. J. of Environmental Research and Public Health, Vol.19, No.15, 2022. https://doi.org/10.3390/ijerph19159299
- [7] Q. Tan et al., “Virtual flight simulation of delivery drone noise in the urban residential community,” Transportation Research Part D: Transport and Environment, Vol.118, Article No.103686, 2023. https://doi.org/10.1016/j.trd.2023.103686
- [8] R. R. Graham, “The silent flight of owls,” The Aeronautical J., Vol.38, No.286, pp. 837-843, 1934. https://doi.org/10.1017/S0368393100109915
- [9] T. Bachmann et al., “Morphometric characterisation of wing feathers of the barn owl Tyto alba pratincola and the pigeon Columba livia,” Frontiers in Zoology, Vol.4, Article No.23, 2007. https://doi.org/10.1186/1742-9994-4-23
- [10] Y. Wei, F. Xu, S. Bian, and D. Kong, “Noise reduction of UAV using biomimetic propellers with varied morphologies leading-edge serration,” J. of Bionic Engineering, Vol.17, No.4, pp. 767-779, 2020. https://doi.org/10.1007/s42235-020-0054-z
- [11] H. M. Lee, Z. Lu, K. M. Lim, J. Xie, and H. P. Lee, “Quieter propeller with serrated trailing edge,” Applied Acoustics, Vol.146, pp. 227-236, 2019. https://doi.org/10.1016/j.apacoust.2018.11.020
- [12] R. Noda, T. Ikeda, T. Nakata, and H. Liu, “Characterization of the low-noise drone propeller with serrated Gurney flap,” Frontiers in Aerospace Engineering, Vol.1, Article No.1004828, 2022. https://doi.org/10.3389/fpace.2022.1004828
- [13] R. Noda, K. Hoshiba, I. Komatsuzaki, T. Nakata, and H. Liu, “Near- and far-field acoustic characteristics and sound source localization performance of low-noise propellers with gapped Gurney flap,” Drones, Vol.8, No.6, Article No.265, 2024. https://doi.org/10.3390/drones8060265
- [14] P. Chaitanya, P. Joseph, S. Narayanan, and J. W. Kim, “Aerofoil broadband noise reductions through double-wavelength leading-edge serrations: A new control concept,” J. of Fluid Mechanics, Vol.855, pp. 131-151, 2018. https://doi.org/10.1017/jfm.2018.620
- [15] K. Hansen, R. Kelso, and C. Doolan, “Reduction of flow induced tonal noise through leading edge tubercle modifications,” 16th AIAA/CEAS Aeroacoustics Conf., 2010. https://doi.org/10.2514/6.2010-3700
- [16] Y. Yang et al., “Experimental study on noise reduction of a wavy multi-copter rotor,” Applied Acoustics, Vol.165, Article No.107311, 2020. https://doi.org/10.1016/j.apacoust.2020.107311
- [17] R. Noda et al., “Development of bio-inspired low-noise propeller for a drone,” J. Robot. Mechatron., Vol.30, No.3, pp. 337-343, 2018. https://doi.org/10.20965/jrm.2018.p0337
- [18] C. P. Ellington and M. J. Lighthill, “The aerodynamics of hovering insect flight. V. A vortex theory,” Philosophical Trans. of the Royal Society B: Biological Sciences, Vol.305, No.1122, pp. 115-144. 1984. https://doi.org/10.1098/rstb.1984.0053
- [19] K. Heutschi, B. Ott, T. Nussbaumer, and P. Wellig, “Synthesis of real world drone signals based on lab recordings,” Acta Acustica, Vol.4, No.6, Article No.24, 2020. https://doi.org/10.1051/aacus/2020023
- [20] M. Alkmim et al., “Drone noise directivity and psychoacoustic evaluation using a hemispherical microphone array,” The J. of the Acoustical Society of America, Vol.152, No.5, pp. 2735-2745, 2022. https://doi.org/10.1121/10.0014957
- [21] J. E. Marte and D. W. Kurtz, “A review of aerodynamic noise from propellers, rotors, and lift fans,” National Aeronautics and Space Administration Technical Report No.32-1462, 1970.
- [22] J. E. F. Williams and D. L. Hawkings, “Sound generation by turbulence and surfaces in arbitrary motion,” Philosophical Trans. of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol.264, No.1151, pp. 321-342, 1969. https://doi.org/10.1098/rsta.1969.0031
- [23] J. E. F. Williams and D. L. Hawkings, “Theory relating to the noise of rotating machinery,” J. of Sound and Vibration, Vol.10, No.1, pp. 10-21, 1969. https://doi.org/10.1016/0022-460X(69)90125-4
- [24] T. Ikeda et al., “Morphology effects of leading-edge serrations on aerodynamic force production: An integrated study using PIV and force measurements,” J. of Bionic Engineering, Vol.15, No.4, pp. 661-672, 2018. https://doi.org/10.1007/s42235-018-0054-4
- [25] X. Zhang, A. Sciacchitano, and S. Pröbsting, “Aeroacoustic analysis of an airfoil with Gurney flap based on time-resolved particle image velocimetry measurements,” J. of Sound and Vibration, Vol.422, pp. 490-505, 2018. https://doi.org/10.1016/j.jsv.2018.02.039
This article is published under a Creative Commons Attribution-NoDerivatives 4.0 Internationa License.