Vertical distribution and vortex structure of rotor wind field under the influence of rice canopy

Li, Jiyu; Shi, Yeyin; Lan, Yubin; Guo, Shuang

doi:10.1016/j.compag.2019.02.027

Cited by 56 publications

(20 citation statements)

References 6 publications

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“…A consistent conclusion was made [36] . Their latest research was about using wind-speed arrays to measure the distribution and the speed of downwash airflow [37] . These are continuous studies on one kind of UAV and the conclusions are more and more in-depth, while Wang utilised a wind measurement system as well as a high-speed camera to find the wind distribution.…”

Section: Key Technology Of Examination Methods Of Uav Downwashmentioning

confidence: 99%

Research status and trends of downwash airflow of spray UAVs in agriculture

Yang

Zheng

Liu

2019

International Journal of Precision Agricultural Aviation

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Downwash airflow of spray UAVs in agriculture has been gradually focused on and a few studies have already been involved in it. Thus, this paper firstly reviewed the current research of downwash airflow of UAVs for agricultural spray. It is found that Chinese scholars have published the majority of the studies in this area. Furthermore, two aspects of this kind of research, one, the work related to the caused results of UAV downwash acting on spray, the other, that regarding downwash itself for investigation, were analysed. It is illustrated that the present research usually uses water-sensitive paper, electronic devices, like wind-speed arrays and PIV, and CFD simulation. However, the existed electronic devices have some limitations, such as lacking of the ability of showing and demonstration of downwash in big enough areas in detail during recording. Moreover, the studies directly related to downwash have been just launched around the world and the examination for multi-rotor UAVs is even seriously not enough. Therefore, in terms of research trends, it is significant to develop specialised sensors for downwash measurement. The general and reliable CFD models of a class of UAVs are also needed. In addition, the combination of UAV downwash with real applications and actual production is important for the clarification of the details in different situations.

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Section: Key Technology Of Examination Methods Of Uav Downwashmentioning

confidence: 99%

Research status and trends of downwash airflow of spray UAVs in agriculture

Yang

Zheng

Liu

2019

International Journal of Precision Agricultural Aviation

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“…Nozzles and adjuvants are important factors affecting the droplet deposition distribution [19,20]. The addition of adjuvants including surfactants, spreaders, stickers, deposition aids, activators, humectants, antifoamers, wetting agents, and drift reduction agents etc., can alter spray performance such as the target deposition, spray droplet size, and deposition characteristics [21].…”

Section: Introductionmentioning

confidence: 99%

Droplet Deposition and Control of Planthoppers of Different Nozzles in Two-Stage Rice with a Quadrotor Unmanned Aerial Vehicle

et al. 2020

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Previous studies have confirmed that choosing nozzles that produce coarser droplets could reduce the risk of pesticide spray drift, but this conclusion is based on a large volume of application, and it is easy to ignore how this impacts the control effect. The difference from the conventional spray is that the carrier volume of Unmanned Aerial Vehicle (UAV) is very limited. Little was known about how to choose suitable nozzles with UAV’s limited volume to ensure appropriate pest control. Droplet deposition with the addition of adjuvant and the LU110-010, LU110-015, and LU110-020 nozzles and control of planthoppers within nozzles treatments were studied by a quadrotor UAV in rice (Tillering and Flowering stages). Allura Red (10 g/L) was used as a tracer and Kromekote cards were used to collect droplet deposits. The results indicate that the density of the droplets covered by the LU110-01 nozzle is well above other treatments, while the differences in droplet deposition and coverage are not significant. The deposition and coverage were improved with the addition of adjuvant, especially in LU110-01 nozzles’ treatment. The control effects of rice planthoppers treated by LU110-01 nozzle were 89.4% and 90.8% respectively, which were much higher than 67.6% and 58.5% of LU110-020 nozzle at 7 days in the Tillering and Flowering stage. The results suggest that selecting a nozzle with a small atomizing particle size for UAV could improve the control effect of planthoppers.

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“…Li et al [24–26] elaborated on the feature of airflow during UAV performance and clarified that the vortex formed in rice and wheat plants was a typical feature of the low-altitude spraying of the rotor UAV. When the droplet size is within a certain range, the spatial mobility of the droplet is primarily determined by the distribution of the wind field [27–28]. Only when the wind field interacts with the crop canopy can the droplets deposit on the crop canopy, so the formation of the vortex is an important index of whether the wind field effectively interacts with the canopy.…”

Section: Introductionmentioning

confidence: 99%

Distribution characteristics on droplet deposition of wind field vortex formed by multi-rotor UAV

Guo¹,

Li²,

Yao³

et al. 2019

PLoS ONE

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When the unmanned aerial vehicle (UAV) is used for aerial spraying, the downwash airflow generated by the UAV rotor will interact with the crop canopy and form a conical vortex shape in the crop plant. The size of the vortex will directly affect the outcome of the spraying operation. Six one-way spraying were performed by the UAV in a rice field with different but random flying altitude and velocities within the optimal operational range to form different vortex patterns. The spraying reagent was clear water, which was collected by water sensitive paper (WSP), and then the WSP was analyzed to study the droplets deposition effects in different vortex states. The results showed that the formation of the vortex significantly influenced the droplet deposition. To be specific, the droplet deposition amount in the obvious-vortex (OV) state was about 1.5 times of that in the small-scale (SV) vortex state, and 7 times of that in the non-vortex (NV) state. In the OV state, the droplets mainly deposited directly below and on both sides of the route. The deposition amount, coverage rate and droplet size increased from top to bottom of the crops with the deposition amount, coverage rate, and volume median diameter (VMD) ranging 0.204–0.470 μL/cm 2 , 3.31%-7.41%, and 306–367μm, respectively. In the SV state, droplets mainly deposited in the vortex area directly below the route. The deposition amount in the downwind direction was bigger than that in the upwind direction. The maximum of deposition amount, coverage rate and droplet size were found in the middle layer of the crops, the range are 0.177–0.334μL/cm 2 , 2.71%-5.30%, 295–370μm, respectively. In the NV state, the droplet mainly performed drifting motion, and the average droplet deposition amount in the downwind non-effective region was 29.4 times of that in the upwind non-effective region and 8.7 times of the effective vortex region directly below the route. The maximum of deposition amount, coverage rate and droplet size appeared in the upper layer of the crop, the range are 0.006–0.132μL/cm 2 , 0.17%-1.82%, 120–309μm, respectively, and almost no droplet deposited in the middle and lower part of the crop. The coefficient of variation (CV) of the droplet deposition amount was less than 40% in the state of obvious-vortex and small-scale vortex, and the worst penetration appeared in the non-vortex amounting to 65.97%. This work offers a basis for improving the spraying performance of UAV.

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Vertical distribution and vortex structure of rotor wind field under the influence of rice canopy

Cited by 56 publications

References 6 publications

Research status and trends of downwash airflow of spray UAVs in agriculture

Research status and trends of downwash airflow of spray UAVs in agriculture

Droplet Deposition and Control of Planthoppers of Different Nozzles in Two-Stage Rice with a Quadrotor Unmanned Aerial Vehicle

Distribution characteristics on droplet deposition of wind field vortex formed by multi-rotor UAV

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