Droplet deposition behavior on the surface of wheat leaves with wind-induced vibration

Abstract

Droplet impingement on leaf surfaces is a common phenomenon in the spray application process. Most impingements have focused on droplet deposition behavior on stationary leaf surfaces. However, airflow movement and auxiliary airflow during the spray application process create disturbances and generate vibrations on the leaves, which would inevitably affect the deposition conditions of droplets on leaf surfaces. A three-dimensional “droplet-leaf vibration” Computational fluid dynamics (CFD) simulation model is constructed in this paper, and model validation and simulation tests are performed to investigate the effects of leaf vibration on droplet deposition. Experimental results reveal that when the droplet velocity is 1 m/s, with a 60° inclination angle and a vibrational angular velocity of 9 rad/s, the spreading area factor of a 200-μm droplet has the greatest increase up to a value of 1.34, and vibrational effects on the deposition behavior of the three droplet diameters demonstrate a consistent trend.Compared to stationary leaves, vibrating wheat leaves can alter the impingement behavior of droplets close to critical conditions, and vibration can also increase the sliding range for droplets. Vibration in wheat leaves can promote droplet spreading and deposition and increase the spreading area of droplets on the leaf surface. The effects of vibration on large-diameter droplets are more significant compared to small-diameter droplets, where droplet spreading and movement can be effectively enhanced. This paper shall provide a three-dimensional “droplet-leaf vibration” CFD simulation method, providing novel research ideas for the study of droplet deposition behavior on vibrating leaves.