Numerical analysis of downwash flow field from quad-rotor unmanned aerial vehicles
Abstract
Abstract: Agricultural drones, also known as Unmanned Aerial Vehicles(UAV), have attracted increasing attention because of their advantages of small size, convenient handling, and the ability to function without a runway, and they are particularly suitable for small farmlands in Asia, especially in China. The downwash flow field caused by the rotors of agricultural drone is one of main characteristics and affects the droplet deposition and drift law. Studying the distribution characteristics and development law of the downwash flow field is the basis for improving the application performance of spray technology applied on agricultural drones. With the development of computational fluid dynamics, agricultural aerial spray modeling has become an area of academic interest. In this study, the numerical simulation method was used to calculate the downwash flow field model of the quad-rotor UAV, to analyze its distribution characteristics and development law over time at different flight speeds. The accuracy of the numerical simulation was verified by field test. The simulation results show that the average velocities of airflow under1.6m from rotors at 2, 4 and6m/s are 2.33 m/s,1.90m/s and1.03m/s, respectively, which are high enough to disturb most of plant canopy and enhance the penetration rate of droplets. The flight velocity of drone has a significant effect on the downwash flow field. With the increase of the flight velocity, the wake of drones is gradually raised, and the concentration of wingtip vortices increases. When the flight velocity is increased to6m/s, the wingtip vortex velocity reaches3.3m/s, which has a strong entrainment effect on the droplets and greatly increases the risk of droplet drift.
Keywords: quad-rotor UAV for plant protection, agricultural drones, downwash flow field, flight velocity
DOI: 10.33440/j.ijpaa.20200304.138
Citation: Zhang H Y, Lan Y B, Shen N W, Wu J Y, Wang T, Han J, Wen S. Numerical analysis of downwash flow field from quad-rotor unmanned aerial vehicles. Int J Precis Agric Aviat, 2020; 3(4): 1–7.
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Lan Y, Chen S , Fritz B K. Current status and future trends of precision agricultural aviation technologies. Int J Agric Biol Eng, 2017; 10(3): 1–17. doi: 10.3965/j.ijabe.20171003.3088
Zhang D, Lan Y, Chen L, et al. Current status and future trends of agricultural aerial spraying technology in china. Transactions of the Chinese Society for Agricultural Machinery, 2014; 45(10): 53–59.
Guo Y, Wang N, Jin B. Development status of unmanned arcraft for agricultural plant protection. Agricultural Engineering, 2017; 7(2): 24–25.
Cheng Z. Annual Development Report of Plant Protection UAV Industry. Shenzhen: Huifei UAV Application Technology Training Center, 2019
Lan Y B, Chen S D. Current status and trends of plant protection UAV and its spraying technology in China. Int J Precis Agric Aviat, 2018; 1(1): 1–9. doi: 10.33440/j.ijpaa.20180101.0002
Li J, Lan Y, Shi Y. Research progress on airflow characteristics and field pesticide application system of rotary-wing UAV. Transactions of the Chinese Society of Agircultural Engineering, 2018; 34(12): 104–118.
Li J, Yao W, Lin J, et al. Three-dimensional wind field measurement system suitable for unmanned aerial vehicles and its use method: CN201610973681.9. 2017-05-17
Li J, Lin J, Lan Y, et al. Wind field measurement platform under drone rotor wing and wind field measurement method using the platform: CN201710151904.5. 2017-08-18
Li J, Huang C, Lan Y, et al. A zero-point adjustable dynamic pressure type wind speed measuring device: CN201610983366.4. 2017-04-19.
Hu L, Zhou Z, Luo X, et al. Design and test of wireless sensor network measurement system for unmanned helicopter wind farm. Transactions of The Chinese Society of Agricultural Machinery?2014; 45(5): 221–226.
Wang P, Hu L, Zhou Z, et al. Wind field measurement for supplementary pollination in hybrid rice breeding using unmanned gasoline engine single-rotor helicopter. Transactions of the Chinese Society of Agircultural Engineering, 2013; 29(3): 54–61.
Li J, Zhou Z, Lan Y, et al. Distribution of canopy wind field produced by rotor unmanned aerial vehicle pollination operation. Transactions of the Chinese Society of Agircultural Engineering, 2015; 31(3): 77–86.
Li J, Zhou Z, Hu L, et al. Optimization of operation parameters for supplementary pollination in hybrid rice breeding using round multi-axis multi-rotor electric unmanned helicopter. Transactions of the Chinese Society of Agircultural Engineering, 2014; 30(11): 1–9.
Li J, Lan Y, Wang J, et al. The distribution of rice pollen based on a small UAV wind field. China Agricultural Abstracts-Agricultural Engineering, 2018; 30(02): 13–19. Available online:
Liu X. Research on distribution regularity of downwash airflow velocity in rotor flow field of single rotor plant protection UAV. Heilongjiang Bayi Agricultural University, 2019;
Tang, Q, et al. Numerical simulation of the downwash flow field and droplet movement from an unmanned helicopter for crop spraying. Computers and Electronics in Agriculture, 2020; 174:105468.
Tang, Q, et al. High-accuracy, high-resolution downwash flow field measurements of an unmanned helicopter for precision agriculture. Computers and Electronics in Agriculture, 2020; 173:105390. doi: 10.1016/j.compag.2020.105468
Tang, Q, et al. Application of an ultrasonic anemometer array to field measurements of the downwash flow of an agricultural unmanned helicopter. Transactions of the ASABE, 2019; 62 (5): 1219–1230.
Wen S, Han J, Lan Y, et al. Influence of wing tip vortex on drift of single rotor plant protection unmanned aerial vehicle. Transactions of the Chinese Society for Agricultural Machinery, 2018; 49(8): 127–137.
Yang F, Xue X, Cai C, et al. Effects of down wash airflow in hover on droplet motion law for multi-rotor unmanned plant protection machine. Transactions of the Chinese Society of Agircultural Engineering, 2018; 34(2): 64–73.
Zhang H, Qi L, Wu Y, et al. Distribution characteristics of rotor downwash airflow field under spraying on orchard using unmanned aerial vehicle. Transactions of the Chinese Society of Agircultural Engineering, 2019; 35(18): 44–54.
Wen S, Han J, Ning Z, et al. Numerical analysis and validation of spray distributions disturbed by quad-rotor drone wake at different flight speeds. Computers and Electronics in Agriculture, 2019; 166: 105036. doi: 10.1016/j.compag.2020.105468
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