Cavity emergence and the increase in drag following the entry of solid spheres into a stratified, two-layer system of immiscible liquids

A new phenomenon associated with the entry of solid spheres into a stratified, two-layer, highly viscous silicone oil-water system had been observed. Following the passage of solid spheres through the oil-water interface, the emergence of an air cavity from within the highly viscous oil thread connecting the spheres to the interface was observed. In addition, the data analysis show that a relatively thin layer of highly viscous upper-layer liquid could absorb significant impact while also significantly increase the drag experienced by relatively larger spheres moving in the less viscous lower-layer liquid.