This work presents an experimental investigation into the dynamics and breakup physics of large water droplets in the diameter range of 10-40 mm. Although droplet and droplet breakup have been studied for over a century, droplets in free fall and droplets larger than the capillary length have rarely been investigated. A novel droplet release mechanism and camera that falls with the droplets acquire video data and enable controlled measurements of these large droplets in free fall. The results provide new insights into droplet stability, oscillation, deformation, and breakup across a spectrum of sizes exceeding the capillary length scale. The work reveals that a larger mesh porosity (up to a reasonable point) and geometries that match droplet diameter release droplets more quickly with less elongation. Moreover, the initial droplet shape after release dictates the resulting breakup modes for some specific sizes. Distinct types of breakup are characterized, including backward bag, stamen with multi-bags, and bag with stamen. Detailed image analyses quantify droplet aspect ratio changes, inflation rates, burst times, and volume distributions over a range of Weber numbers. These findings offer insights into large droplet mechanics in regimes relevant to free fall fluid releases such as aerial firefighting, fluid falling from pipes, and industrial droplet systems.

Biography

Aqeel Almanashi is a mechanical engineer and Ph.D candidate specializing in experimental fluid dynamics. He earned his BS in Mechanical Engineering from KFUPM in 2018, followed by an MS from KAUST in 2020. Currently pursuing his Ph.D. at KAUST since 2021, Aqeel's research focuses on large droplet release and breakup at the splash lab.