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Abstract.

The down-wash air flow generated by Unmanned aerial vehicles (UAV) rotor wings can significantly improve the penetrability of droplets. This means that the air flow helps the droplets to be deposited inside the canopy or on the lower surfaces of leaves. For now, few publications have highlighted the cause of such phenomena. Using the k-ε turbulence model in Solid Works platform, this paper simulated reversing effect of leaves caused by the down-wash air flow during aerial pesticide application. The simulated result shows that air flow can create a pressure difference between the upper and lower surfaces of the leaf which subsequently causes a torque on it. Since the torque on the Z direction is greater than on either the X or Y direction, the leaf is reversed around Z axis hence the droplets deposit inside the canopy or on the upper and lower surfaces. The torque decreases when the leaf gets closer to the center of air flow field within a radius of 200mm. The field test results show that the average deposition droplets number is 10.8 on the upper surface and 4.0 on the lower surface, which basically coincides with the simulation results. This paper offers a theoretical explanation of the cause of formation of the reversing effect of leaves caused by the down-wash air flow during the aerial pesticide application and provides a reference for the optimization of aerial operation parameters