Bursting water balloons

TL;DR

This study experimentally investigates the impact, rupture, and subsequent fluid instabilities of water-filled balloons on a rigid surface, revealing phenomena related to the Richtmyer-Meshkov instability even without density differences.

Contribution

It demonstrates the occurrence of Richtmyer-Meshkov-like instabilities in water balloons, including cases without density contrast, expanding understanding of fluid interface instabilities.

Findings

Observation of wave formation on the balloon surface due to impact

Identification of shear instability after membrane rupture

Detection of interface growth resembling Richtmyer-Meshkov instability without density difference

Abstract

The impact and rupture of water-filled balloons upon a flat, rigid surface is studied experimentally, for which three distinct stages of the flow are observed. Due to the impact, waves are formed on the balloon's surface for which the restoring force is tension in the latex. Immediately following rupture of the membrane, a shear instability created by the retraction of the balloon is observed. At later times, a larger-scale growth of the interfacial amplitude is observed, that may be regarded as a manifestation of a phenomenon known as the Richtmyer-Meshkov instability. This flow is closely related to the classical understanding of the Richtmyer-Meshkov instability for when there exists a density difference between the fluids inside and outside the balloon. Further, it is shown experimentally that this growth of the interface may also occur when there is no density difference across the balloon, a situation that does not arise for the standard Richtmyer-Meshkov instability.