Numerical simulation of downwash airflow distribution inside tree canopies of an apple orchard from a multirotor unmanned aerial vehicle (UAV) sprayer

Zhang, Hao; Qi, Lijun; Wan, Junjie; Musiu, Elizabeth M.; Zhou, Jiarui; Lu, Zhongao; Wang, Pei

doi:10.1016/j.compag.2022.106817

Cited by 24 publications

(10 citation statements)

References 44 publications

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“…In a deeper canopy, the flow loss becomes more severe. 12 In this condition, the flipping effect on branches and leaves and the ability of flow to carry small droplets towards lower canopy layers will tend to be reduced. The obstruction effect of the canopy on downwash flow intensifies deposition inhibition within the canopy, with weak overall spray penetration.…”

Section: Different Types Of Crops Require Differing Targeting Solutionsmentioning

confidence: 99%

“…Within the canopy, the air flow is hindered by branches and leaves, causing a decrease in speed and an overall momentum loss. In a deeper canopy, the flow loss becomes more severe 12 . In this condition, the flipping effect on branches and leaves and the ability of flow to carry small droplets towards lower canopy layers will tend to be reduced.…”

Section: Different Types Of Crops Require Differing Targeting Solutionsmentioning

confidence: 99%

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Challenges and opportunities of unmanned aerial vehicles as a new tool for crop pest control

Hewitt

Chen

et al. 2023

Pest Management Science

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The application of pesticides is not simply delivering chemicals to the target area. It also involves considering the negative aspects and developing strategies to deal with them during the application process, to ensure the maximization of pesticides use efficiency and the maintenance of the ecosystem. Unmanned aerial vehicle (UAV) sprayers demonstrate unique advantages compared to traditional ground sprayers, particularly in terms of maneuverability and labor intensity reduction, showed great potential for chemical application in pest control. It is undeniable that there exist challenges in the practice of UAV spraying, such as higher potential risks of pesticide drift or pathogen transmission, uncertainty canopy deposition for different crops, and unexpected leaf breakage induced by downwash flow. Maximizing the utilization of downwash flow while avoiding lateral air movement outside the intended target crop area is a major issue for chemical application with UAV sprayers, particularly in light of the increasingly apparent consensus on the need for enhanced environmental protection during the chemical application process. It must be considered that the operation strategy in different scenarios and for different crop targets is not the same, unique requirements should be given on nozzle atomization, flight parameters, adjuvants and aircraft types in specific working situation. In future, the implementation of spray drift prediction, technical procedures development, and other solutions aimed at reducing pesticide drift and improving deposition quality, is expected to to promote the adoption of UAV sprayers by more farmers.This article is protected by copyright. All rights reserved.

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Section: Different Types Of Crops Require Differing Targeting Solutionsmentioning

confidence: 99%

Section: Different Types Of Crops Require Differing Targeting Solutionsmentioning

confidence: 99%

Challenges and opportunities of unmanned aerial vehicles as a new tool for crop pest control

Hewitt

Chen

et al. 2023

Pest Management Science

View full text Add to dashboard Cite

show abstract

“…Due to their cost efficiency and numerous possibilities for use in a wide range of civil, commercial and industrial applications (inspection of power lines, inspection of road infrastructure, bridges, inspection of oil pipelines, inspection of industrial facilities of strategic interest, e.g., oil refineries, nuclear power plants, inspection of disaster areas), multirotor UAVs have already been the subject of study for more than a decade. Since then, numerous research studies have been carried out on the modelling [ 33 , 34 , 35 ] and design of actuation, command and control systems [ 36 ] and the development of various design solutions [ 37 , 38 ]. Despite the abundance of the scientific literature, the topicality of the subject remains high, due to the subtle balance between the sensor features and involved outlays.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Hexacopter UAVs Attitude Parameters Employing Control and Decision Support Systems

Stamate

Pupăză

Nicolescu

et al. 2023

Sensors

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Today, there is a conspicuous upward trend for the development of unmanned aerial vehicles (UAVs), especially in the field of multirotor drones. Their advantages over fixed-wing aircrafts are that they can hover, which allows their usage in a wide range of remote surveillance applications: industrial, strategic, governmental, public and homeland security. Moreover, because the component market for this type of vehicles is in continuous growth, new concepts have emerged to improve the stability and reliability of the multicopters, but efficient solutions with reduced costs are still expected. This work is focused on hexacopter UAV tests carried out on an original platform both within laboratory and on unrestricted open areas during the start–stop manoeuvres of the motors to verify the operational parameters, hover flight, the drone stability and reliability, as well as the aerodynamics and robustness at different wind speeds. The flight parameters extracted from the sensor systems’ comprising accelerometers, gyroscopes, magnetometers, barometers, GPS antenna and EO/IR cameras were analysed, and adjustments were performed accordingly, when needed. An FEM simulation approach allowed an additional decision support platform that expanded the experiments in the virtual environment. Finally, practical conclusions were drawn to enhance the hexacopter UAV stability, reliability and manoeuvrability.

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“…In terms of downwash, wind speed sensors, 10 cameras 11,12 and water-sensitive papers 13 are generally used to record downwash velocities, droplet trajectories, high-speed particle images, droplet deposition and penetration. In addition, some studies conducted computational fluid dynamics (CFD) to obtain the flow field and distribution of downwash, 14,15 to demonstrate the ground effect of spatiotemporal distribution 16 and to investigate the influence of rotors on droplets, deposition and drift. 17 For crosswind, the research approaches are similar.…”

Section: Introductionmentioning

confidence: 99%

Back pressure generated by downwash and crosswind on spatial atomization characteristics during UAV spraying: CFD analysis and verification

Feng,

Xu,

Yang

et al. 2023

Pest Management Science

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BackgroundDuring unmanned aerial vehicles (UAVs) spraying, downwash and crosswind generate back pressure in comprehensive, which changes in spatial atomization characteristics of spraying droplets. However, the process of such atomization characteristics needs to be clarified. This study focuses on the effect of rotor speed and crosswind speed on spatial atomization characteristics. The computational fluid dynamics (CFD) models of the distributions of airflow, back pressure and atomization characteristics were established, and verification was conducted by developing a validation platform.ResultsThe CFD results indicated that small droplets of 65 μm to 130 μm atomized by negative pressure would be coalesced near the nozzle, while large droplets of 390 μm to 520 μm atomized by positive pressure would be aggregated further away. Crosswind caused atomization stratification with droplet sizes of about 90 μm, about 320 μm and about 390 μm. When crosswind speed increased from 3 m/s to 6 m/s, the spraying drifted from 0.5 m to 1 m. When rotor speed increased from 2000 RPM to 3000 RPM, droplet distribution was expanded and droplet particle size was more uniform. Verification results demonstrated that the spraying distribution and the droplet size variation were consistent with the CFD.ConclusionsSpatial atomization characteristics were highly correlated with airflow and back pressure. Moreover, as crosswind generated droplet drift and atomization stratification and downwash could improve the uniformity of droplet distribution, spraying performance was superior by enhancing downwash to restrain the adverse effect of crosswind in the real application.This article is protected by copyright. All rights reserved.

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Numerical simulation of downwash airflow distribution inside tree canopies of an apple orchard from a multirotor unmanned aerial vehicle (UAV) sprayer

Cited by 24 publications

References 44 publications

Challenges and opportunities of unmanned aerial vehicles as a new tool for crop pest control

Challenges and opportunities of unmanned aerial vehicles as a new tool for crop pest control

Improvement of Hexacopter UAVs Attitude Parameters Employing Control and Decision Support Systems

Back pressure generated by downwash and crosswind on spatial atomization characteristics during UAV spraying: CFD analysis and verification

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