Drop impact onto a substrate wetted by another liquid: corona detachment from the wall film

Abstract

Drop impact onto a thin liquid film of another liquid is observed and characterized using a high-speed video system. A new mode of splash - a complete, simultaneous corona detachment - has been observed, which is the result of the lamella breakup near the wall film. The abrupt outward and upward displacement of the lamella leads to an extreme stretching of the corona wall, resulting in its rapid thinning and a rupture. This rupture triggers propagating Taylor-Culick rims, which rapidly spread, meet and, thus, undercut simultaneously the entire corona, resulting in its detachment. Special experiments with the spreading corona impingement onto a fixed needle, supplement the physical evidence of the above-mentioned mechanism. A self-consistent theory of the observed phenomena is proposed and compared with experiments, exhibiting good agreement.