Dynamics of cavitation bubbles in a liquid layer

Abstract Cavitation phenomena are widespread in nature and industrial applications. Researchers have conducted in‐depth studies on the interaction of cavitation bubbles with a single boundary. However, when cavitation bubbles interact simultaneously with multiple boundaries, for example, a rigid wall and free surface, the process and mechanisms are still unclear. Here, experiments are carried out to study the dynamics of cavitation bubbles within a liquid layer. The results show that due to the combined effect of a rigid wall and free surface, the bubbles exhibit a significant downward migration in the liquid layer. Based on Kelvin impulse theory, we calculate the impulse experienced by the bubble and find a good consistency between the downward migration of the bubble and the impulse it experiences. By varying the initial position of the bubble in the liquid layer, we find that the confinement effect of the rigid wall significantly affects the bubble's collapse morphology, leading to different post‐collapse phenomena of free surface motion.