Acoustics of cubic bubbles: six coupled oscillators

TL;DR

This paper introduces cubic bubbles anchored to 3D printed frames, demonstrating their stability, coupled oscillations, and potential as efficient monopole acoustic emitters in water.

Contribution

It presents the first analytical and numerical models of cubic bubbles' coupled oscillations and acoustic properties, advancing bubble-based acoustic research.

Findings

Cubic bubbles are more stable than spherical ones.

Each face acts as a coupled harmonic oscillator.

Cubic bubbles are effective monopole sub-wavelength emitters.

Abstract

In this manuscript we introduce cubic bubbles that are pinned to 3D printed millimetric frames immersed in water. Cubic bubbles are more stable over time and space than standard spherical bubbles, while still allowing large oscillations of their faces. We found that each face can be described as a harmonic oscillator coupled to the other ones. These resonators are coupled by the gas inside the cube but also by acoustic interactions in the liquid. We provide an analytical model and 3D numerical simulations predicting the resonance with a very good agreement. Acoustically, cubic bubbles prove to be good monopole sub-wavelength emitters, with non-emissive secondary surfaces modes.