Analyzing Acoustic Damping Effects in Bubble Oscillations Across Various Liquids

The study of acoustic interactions between sound fields and bubbles has diverse applications in medicine, engineering, and biology, including optimizing ultrasound imaging, reducing watercraft damage, and advancing our understanding of aquatic animal biology. The study of sound-bubble interactions also provides a flexible tool since bubbles can be modeled using theoretical frameworks, such as simple harmonic oscillators. Our investigation focuses on modeling vibrating bubbles in various liquids as harmonic oscillators. Our research is motivated by a common Brazilian practice used to assess alcohol content, where the sound of a partially filled bottle being struck changes if the bottle is quickly inverted beforehand. This distinct sound results from the liquid’s state, particularly the bubbles formed within it. Specifically, this sound difference can be attributed to the damped oscillations of the induced bubbles in the viscous liquid. We recorded the sound spectrum before and after the rotation to compare peak frequencies. Liquids were categorized based on how long they maintained the sound difference, quantifying the damping phenomenon using quality factors from a Lorentzian fit of the sound spectrum. This established a direct relationship between the oscillation’s period and amplitude and the liquid's properties. Results indicated that as viscosity increases, the quality factor decreases, reducing bubble vibrations and causing the sound difference to fade more quickly. This study highlighted the role of viscous damping as a sound attenuator and successfully demonstrated the relationship between emitted frequencies in different beverages, enhancing our understanding of bubble dynamics.