A Fast Analysis of Pesticide Spray Dispersion by an Agricultural Aircraft Very near the Ground

Abstract

This study provides a fast analysis of pesticide spray trails and dispersion influenced by crosswind, headwind, velocity field and the wake of an agricultural aircraft approaching the ground, to improve operational efficiency and reduce environmental impact. The lifting line-wingtip vortices mixture model is proposed to calculate induced velocity field around a monoplane far to 190 wingspans downstream, and N-vortex system based on point vortex dynamics is applied to simulate vortex rebound and vortex motion on considering extreme ground effect. The droplet trajectories governed by wake vortices and their induced velocity field are therefore determined under the Lagrangian framework. According to the ground deposition of typical droplets, the Gaussian mixture model is employed to predict droplet drift or dispersal for the whole spectrum of droplets in the spanwise direction. The fast analysis is compared to AGDISP and computational fluid dynamics (CFD) simulation for Thrush 510G aircraft, which runs on a common personal computer (CPU 2 GHz, memory 2 GB) within 3.2 s, faster than AGDISP and CFD, and does not rely on swath width input needed by AGDISP. The results suggest crosswind speed and droplet size are two leading factors affecting the drift and ground deposition. To increase droplet size or reduce the portion of fine droplets, the pesticide drift can be suppressed in some degrees.

Droplet deposition and pest control efficacy on pine trees from aerial application

“…The influence of flight parameters, particularly flight path, also was noteworthy. There are differences in the deposition directly below and on either side of a flight path due to the rotor airflow and nozzle arrangement 19,37 . In addition, it is clear that the droplet deposition of different treatments also showed significant differences, especially for T1, which was significantly higher than that of T2 and T3.…”

“…There are differences in the deposition directly below and on either side of a flight path due to the rotor airflow and nozzle arrangement. 19,37 In addition, it is clear that the droplet deposition of different treatments also showed significant differences, especially for T1, which was significantly higher than that of T2 and T3. With the same spray rate (15 L ha −1 ) for all treatments, the average This was caused mainly by the type of nozzle used in the spraying operation.…”

“…Compared to biological control 15 and silvicultural control, 16 which are green and nonpolluting but have a long control cycle, chemical control, which is fast and efficient, is more suitable for pine pest control 17 . Aerial spraying by aircraft has been a popular method of chemical control in recent years, with the advantages of flexibility, low cost and high operational efficiency, and is particularly appropriate for large‐scale forestry operations in mountainous areas 18,19 …”

“…17 Aerial spraying by aircraft has been a popular method of chemical control in recent years, with the advantages of flexibility, low cost and high operational efficiency, and is particularly appropriate for large-scale forestry operations in mountainous areas. 18,19 Several studies have been carried out on the control of MAH by aerial application. [20][21][22] In China, aerial application of insecticides to MAH was adopted as early as 1984, but then the research stagnated for the next 30 years and only gradually re-emerged in 2011.…”

The Effect of Vortex Generators on Spray Deposition and Drift from an Agricultural Aircraft

“…Using CFD models, Ryan et al [16] showed how crosswinds interact with aircraft wake and facilitates the movement of spray droplet trajectories from a near-field to far-field spray target. King et al [17] used a similar modeling approach and reported that crosswind and droplet size are the two important factors affecting drift and off-target deposition.…”