The Effects of Crosswind Speed on the Droplet Deposition Distribution of Thrush 510G Aircraft

Abstract

HighlightsThe penetration ability of droplet in the crop canopy was in a negative correlation with wind speed.The high wind speed was conducive to the deposition of droplet on the crop canopy in the deposition area.The smaller the wind speed was, the more uniform the distribution of droplets became, and the worse the uniformity of droplet penetration.Abstract. Large plant protection fixed-wing aircrafts are widely used for crop spraying in Northeast China, because their working efficiency matches farm size. However, the spray droplet deposition and drift associated with manned fixed-wing aircraft has not been fully understood in China. The objectives of this study were to quantify effects of the small gradient crosswind speeds of 1.10, 0.83, and 0.58 m/s on the distribution and drift of droplets on soybean in the field. Water-sensitive paper (WSP) was used to collect the droplets on the upper canopy and lower parts of the plant. The results showed that the percentage of droplet deposition (the percentage of droplet deposition on the lower layer to that on the canopy of soybean plant) negatively correlated with the crosswind speeds. The crosswind speed had a significant influence on the deposition of droplets on the canopy and penetration performance. When the crosswind speed was 1.10 m/s, the deposition of droplet on the canopy was maximum and the average value of droplet penetration percentage was minimum, which was 6.11 µL and 50.6%, respectively. The average volume median diameters (VMD or DV0.5s) from all in-swath WSPs of three treatments were all smaller than that of droplet spectrum. The variation coefficients of droplet density in three treatments were 46.8%, 39.6%,and 34.1%, respectively, which indicated that the smaller the wind speed was, the more uniform the distribution of droplets became. The results revealed the influence of crosswind speed on the droplet distribution of large fixed-wing aircraft, which was of great significance to improve the operation. Keywords: Droplets distribution, Penetration, Uniformity performance, Wind speed.