Growth and collapse of an acoustically generated cavitation bubble*

Acoustic cavitation has been used for a variety of applications including therapeutic ultrasound procedures (e.g., lithotripsy, histotripsy), ultrasonic cleaning. When a gas nucleus is exposed to strong transient rarefaction waves, it undergoes an explosive growth and violent collapse, leading to the generation of shock waves and large deformation of surrounding materials, which may damage the nearby rigid surface or biological tissue. However, the relation between input parameters (e.g., external waveform, nucleus size) and outputs (e.g., maximum bubble radius and energy concentration at collapse), which is relevant to predict damage, is not fully determined to the larger parameter space and complex physics involved in the bubble oscillation. In this study, we develop a framework for energy transfer in the system to distinguish the major effects determining the bubble dynamics. Using this framework, we obtain the scaling relations to describe the bubble stretch during the growth and energy concentration at collapse using the external waveforms and nucleus size. These relations for a gas bubble in liquid may help us to estimate the damage potential and develop better strategies to control cavitation bubbles and provide a baseline to further investigate the cavitation-induced damage in tissue.