Abstract:
Multirotor Unmanned Aerial Vehicles (UAVs) as agricultural spraying drones have
now become an integral part of the modern agricultural system. They are being used for
spraying on the crops to protect the plants from different types of pests. When spray is
distributed on the crops, it flows away from the target because of the wind field being
created around the UAV. The downwash effect produced by the UAV significantly
influences the spray deposition on crops. The downwash airfield generated by the
hexacopter brings droplets to the crops, increasing the droplets’ deposition on the crops.
Lattice Boltzmann Method was applied using CFD package XFlow to study the downwash
field created by the hexacopter. The primary focus of the research is the downwash airflow
field generated by the hexacopter that affects the motion distribution of droplets released
from the sprayer at different flight speeds and altitudes. Previous research is limited to
downwash effects on a drone with a wheelbase of 1000 mm. In this study, the downwash
effect on a hexacopter drone with a spraying capacity of 30L and a wheelbase of 1900 mm
is studied. We compared the results of our larger-wheelbase UAV with existing
benchmarks. The UAV showed enhanced performance, achieving coverage and penetrable
areas approximately double those of the benchmark. Based upon the results, the optimum
flight height and flight velocity for spraying operation are 3 m and 4 ms-1 respectively
under the condition of coverage and penetrable area.
