(582a) Characterization of Particle Laden Drop Impacts Based on Particulate Properties: Application to Atmospheric-Ocean Transport.

For decades studies have been performed to characterize the impact of liquid drops onto targets. A majority of the experiments were the drops impacting a solid substrate as such a system is relevant for improving technologies for drug delivery, additive manufacturing, and plasma coating. Fewer studies involving the drop falling into a deep pool have been done. Even less is known about the liquid-liquid system when the drop is either coated or filled (laden) with particulates. Deep pool studies are important because they simulate phenomena that occur naturally in our environment and that can impact our health and technology. For instance, pollution in the ocean changes the chemistry of the ocean, consequently impacting our weather prediction and radar systems. One common vector for these pollutants to cross the sea-air interface is raindrops. For our study, we created a simplified system to simulate pollutant-laden raindrops impacting the ocean. Utilizing high speed imaging we characterized the effects of seeding density and properties of the particulates (specifically density and size) on the splash phenomena and end destination of the particulates. Additionally, impact velocities were varied by changing drop height, to compare within and between known splash regimes. From the currently collected data, we see a dominating influence of particle density and inertial forces on the end destination of particulates while the splash phenomena are dictated by the liquid’s properties. This suggests that as rain falls into the ocean, the destination of the entrained pollutants, and thus how easily they are transported elsewhere, will depend on the pollutant’s density and the terminal impact velocity of the pollutant-laden raindrop.