Droplet Dispersion and Coverage in UAV-Based Aerial Firefighting under Adverse Conditions

Aerial firefighting plays a crucial role in wildfire suppression, especially in high-risk or remote areas such as mountainous terrain and dense forests. However, these operations are often hindered by adverse weather (e.g., strong winds and varying temperatures), which can ground manned aircraft and halt aerial suppression efforts. Additionally, drop effectiveness is influenced by terrain and vegetation, as a dense canopy can impede how much of the firefighting agent reaches the ground. In this study, we conduct an experimental investigation of water drop deployment under these adverse conditions. Through a combination of laboratory and scaled field experiments, we examine the fluid dynamics of water drops released. We characterize how variations in payload volume and nozzle release mechanism affect the resulting drop pattern, ground coverage area, and canopy penetration. Environmental factors including wind speed, wind direction, humidity, and temperature are systematically varied to assess their impact on droplet dispersion and deposition. Preliminary results identify the influence of nozzle configurations and drop sizes on ground coverage and vegetation penetration even in high-wind conditions. These findings offer guidance for optimizing payload release strategies and inform the design of low-cost, rapidly deployable UAV firefighting systems for use when manned aircraft are grounded.