Study on Surface Active Bubble Dynamics Properties under Strong Low-Frequency Sound Waves

Abstract

This paper delves into the dynamics of surface-active bubbles under low-frequency acoustic waves, with a focus on the stability effect and basic principle of rupture. The Rayleigh-Plesset equation is extended and modified based on real biological data, resulting in a model of surface-active bubbles with nonlinear surface tension. Using the Runge-Kutta method for numerical calculations, it is observed that larger acoustic wave amplitudes lead to larger bubble amplitudes. The acoustic wave frequency only affects the bubble vibration frequency in the low-frequency range, but at the resonance frequency, the bubble oscillations are violent. To further explain bubble rupture, the stress-strain relationship of the surface active layer of the bubble is studied, with the stress on the wall increasing sharply with the bubble radius. The stability of the non-spherical interface of the surface-active bubbles reveals a critical radius value, with bubbles in a stable state when the radius is smaller than this value. Through simulation, it is observed that bubbles vibrate in a steady state under stable conditions, but when the radius exceeds the critical value, a non-spherical interface appears ultimately resulting in inward depression and rupture.