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arXiv · 2209.03659

Conical-focusing: Mechanism for singular jetting from collapsing drop-impact craters

Yuan Si Tian·Zi Qiang Yang·Sigurður T. Thoroddsen
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Abstract

Fast microjets can emerge out of liquid pools from the rebounding of drop-impact craters, or when a bubble bursts at it surface. The fastest jets are the narrowest and are a source of aerosols both from the ocean and a glass of champagne, of importance to climate and the olfactory senses. The most singular jets, which have a maximum velocity of 137$\pm$4 m/s and diameter of 12 $\mu$m under reduced ambient pressure, are produced when a small dimple forms at the crater bottom and rebounds without pinching off a small bubble. The rebounding of this dimple is purely inertial but highly sensitive on initial conditions. High-resolution numerical simulations reveal a new focusing mechanism, which drives the fastest jet within a converging conical channel, where an entrained air-sheet provides effective slip at the outer boundary of the conically converging flow into the jet. This configuration bypasses any viscous cut-off of the jetting speed and explains the extreme sensitivity observed in detailed experiments of the phenomenon.

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Yuan Si Tian, Zi Qiang Yang, Sigurður T. Thoroddsen. 2022-09-08. Conical-focusing: Mechanism for singular jetting from collapsing drop-impact craters. https://doi.org/10.1017/jfm.2022.1085

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