Breakup of Air Bubbles in Water: Memory and Breakdown of Cylindrical Symmetry

TL;DR

This study uses high-speed video to analyze how air bubbles detach from underwater nozzles, revealing that asymmetries are preserved during breakup and that the process differs from typical singularities due to the influence of interfacial tension.

Contribution

It demonstrates that initial asymmetries in bubble shape are retained during detachment, showing a non-universal singularity influenced by nozzle shape and tilt.

Findings

Asymmetries are preserved during bubble pinch-off.

The minimum neck radius scales with time until breakup.

Air appears to tear rather than pinch in final stages.

Abstract

Using high-speed video, we have studied air bubbles detaching from an underwater nozzle. As a bubble distorts, it forms a thin neck which develops a singular shape as it pinches off. As in other singularities, the minimum neck radius scales with the time until breakup. However, because the air-water interfacial tension does not drive breakup, even small initial cylindrical asymmetries are preserved throughout the collapse. This novel, non-universal singularity retains a memory of the nozzle shape, size and tilt angle. In the last stages, the air appears to tear instead of pinch.