Experimental Study of the Underwater Shock Wave and Impact upon Non-Spherical Collapse of a Cavitation Bubble near the Combined Boundaries.*

Cavitation of liquid can occur when the liquid pressure becomes sufficiently small. It is well known that the cavitation bubbles can cause damage to the fluid machinery. Therefore, the bubble dynamics have been an important research topic for a long time. In particular, numerous studies have focused on understanding the behavior of bubbles near a single boundary (for example, a rigid wall, a free surface, an elastic boundary, etc.). In recent years, further research on the bubble dynamics near multiple boundaries have also been conducted. To provide a deeper understanding of how the cavitation bubble dynamics can be affected by the surrounding boundaries, we focus on the non-spherical collapse of a bubble under the influence of them.

In this study, we experimentally investigated the dynamics of laser-induced cavitation bubble near two boundaries with different rigidities.

We monitor the behavior of a laser-induced cavitation bubble by using a high- speed camera. We are particularly interested in the collapsing and rebounding dynamics such as the jet formation of the bubble affected by the boundaries. In addition, we aim to visualize the underwater shock waves for more comprehensive understanding. We couple these visualizations with the force sensing at the boundary to reveal the unique feature of this bubble behavior and its mechanical effect.