The Bouncing Jet: A Newtonian Liquid Rebounding off a Free Surface

TL;DR

This paper demonstrates that Newtonian liquid jets can bounce off a moving liquid bath due to a thin air film, showing stable bouncing behavior with hysteresis, unlike previous non-Newtonian observations.

Contribution

It reveals that Newtonian fluids can exhibit bouncing jets when the bath moves, expanding understanding beyond non-Newtonian fluids and identifying conditions for stability.

Findings

Bouncing jets occur in various Newtonian fluids like mineral oil.

Bouncing is stabilized by a thin air film and relative motion.

The phenomenon shows hysteresis and multiple steady states.

Abstract

We find that a liquid jet can bounce off a bath of the same liquid if the bath is moving horizontally with respect to the jet. Previous observations of jets rebounding off a bath (e.g. Kaye effect) have been reported only for non-Newtonian fluids, while we observe bouncing jets in a variety of Newtonian fluids, including mineral oil poured by hand. A thin layer of air separates the bouncing jet from the bath, and the relative motion replenishes the film of air. Jets with one or two bounces are stable for a range of viscosity, jet flow rate and velocity, and bath velocity. The bouncing phenomenon exhibits hysteresis and multiple steady states.