Experimental Characterization of Water Droplet Dynamics in Sprinkler Irrigation Using High-Speed Photography

Abstract

A clear understanding of water droplet formation and distribution dynamics is fundamental to improving the hydraulic performance and operational efficiency of sprinkler irrigation systems. This study presents an experimental investigation of droplet characteristics using high-speed photography under controlled laboratory conditions. The objective was to analyze droplet diameter, ellipticity, frequency, and velocity at working pressures of 0.2, 0.25, and 0.3 MPa. Median droplet diameters measured at 6–8 m from the nozzle were 2.79 mm, 3.41 mm, and 3.68 mm at 0.2 MPa, with a reduction of up to 17.7% as pressure increased to 0.3 MPa. Smaller droplets were predominantly concentrated near the nozzle and decreased with radial distance, influencing water application uniformity. Morphological parameters such as uniformity (1.3), ellipticity (2.13), and circularity (0.81) were quantified. Cumulative frequency curves revealed 12% droplet fragmentation at 7–8 m under higher pressures, illustrating the dynamic nature of droplet breakup. A strong linear correlation between droplet diameter and calibrated reference diameter confirmed the reliability of the measurement technique. These findings demonstrate that high-speed photography is a robust method for droplet characterization and provides accurate, repeatable data essential for optimizing sprinkler designs to reduce water loss due to evaporation and wind drift. The study contributes to precision irrigation research by offering a detailed understanding of droplet behavior under varying operating pressures.