DETERMINATION OF SPRAY DRIFT CHARACTERISTICS OF A RONNIE BAUGH TRACTOR-TRAILED BOOM SPRAYER USING COMPUTATIONAL FLUID DYNAMICS

Spray drift leads to wastage of spraying material and poses a threat to non-targeted crops and the environment. Therefore, the spray drift characteristics of a Ronnie Baugh (RB) tractor-trailed boom sprayer were determined through computational fluid dynamics to assist in designing the tractor for boom spraying with minimized spray drift. The wake region of the RB tractor was characterized by investigating its velocity profile, turbulent kinetic energy, and drag coefficient at different forward speeds. Additionally, spray droplet sizes and drift distances from the boom sprayer were measured at forward speeds of 4, 6, and 8 km/h, along with different wind directions. The RB tractor exhibits an estimated drag coefficient of 0.7. The results further demonstrate that, at varying forward speeds, the wake experiences low turbulent kinetic energy and minimal velocity profile variations. No spray drift was observed at tractor speeds below 4 km/h, whereas a drift of 0.19 m and 0.33 m is predicted at 6 km/h and 8 km/h, respectively. The tractor's wake is significantly influenced by changes in wind direction, resulting in varying drift distances from each nozzle due to exposure to both free and obstructed airflow. To minimize drift at higher travel speeds, it is recommended that the tractor be operated in line with the prevailing wind direction.