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.

Dancing ejecta

“…Besides the prompt splash (Thoroddsen 2002;Josserand & Zaleski 2003), the tip of the ejecta can disintegrate into microdroplets by a slingshot mechanism under conditions where the sheet bends down and ruptures where it hits the liquid layer (Thoroddsen et al 2011;Moore, Whiteley & Oliver 2018). More splashing mechanisms have been proposed to drive multiple instabilities and nonlinearity of the crown breakup (Yarin & Weiss 1995;Krechetnikov & Homsy 2009;Bisighini et al 2010;Zhang et al 2010;Wang et al 2018;Stumpf et al 2023). Splashing thresholds have been obtained (Vander Wal, Berger & Mozes 2006;Kittel, Roisman & Tropea 2018) in forms that are reminiscent of the drop impact on a solid surface (Stow & Hadfield 1981;Mundo, Sommerfeld & Tropea 1995).…”

“…2018; Stumpf et al. 2023). Splashing thresholds have been obtained (Vander Wal, Berger & Mozes 2006; Kittel, Roisman & Tropea 2018) in forms that are reminiscent of the drop impact on a solid surface (Stow & Hadfield 1981; Mundo, Sommerfeld & Tropea 1995).…”