Macroscopic acousto-mechanical analogy of a microbubble

TL;DR

This paper introduces a macroscopic acousto-mechanical analogy using coupled pendula to model and analyze the complex oscillatory behavior of microbubbles under acoustic excitation, providing an alternative to expensive experiments.

Contribution

It presents a novel analogy between microbubble dynamics and a ring of coupled pendula, enabling simplified investigation of microbubble oscillations.

Findings

Observation of parametric vibration modes in the pendula ring

Mode mixing phenomena demonstrated through simulations

Relevance of the analogy discussed as an alternative analysis method

Abstract

Microbubbles, either in the form of free gas bubbles surrounded by a fluid or encapsulated bubbles used currently as contrast agents for medical echography, exhibit complex dynamics under specific acoustic excitations. Nonetheless, considering their micron size and the complexity of their interaction phenomenon with ultrasound waves, expensive and complex experiments and/or simulations are required for their analysis. The behavior of a microbubble along its equator can be linked to a system of coupled oscillators. In this study, the oscillatory behavior of a microbubble has been investigated through an acousto-mechanical analogy based on a ring-shaped chain of coupled pendula. Observation of parametric vibration modes of the pendula ring excited at frequencies between $1$ and $5$ Hz is presented. Simulations have been carried out and show mode mixing phenomena. The relevance of the analogy between a microbubble and the macroscopic acousto-mechanical setup is discussed and suggested as an alternative way to investigate the complexity of microbubble dynamics.