Shock waves induced by bubble collapse near a sphere

Nearby structures exert a significant influence on bubble collapse characteristics, including shock wave intensity and liquid jet direction. Understanding the occurrence of these shock waves and liquid jets, as well as predicting their intensity, is crucial for assessing their potential impact on the implosion of deep-sea pressure vessels. In this study, high-fidelity numerical simulations are performed to investigate the collapse behavior of bubbles near a spherical wall. Quantitative analyses are conducted on bubble morphology, shock wave generation, and their impact on the spherical wall. The numerical results reveal that the presence of the spherical wall alters the collapse velocity of the bubble interface. Specifically, the fluid between the bubble and the spherical wall converges to form a high-speed liquid jet propagating in the opposite direction, which impacts the left bubble interface and induces inward concavity. The velocity on the right side of the bubble can exceed the sound speed of the fluid, resulting in higher collapse pressure. After the bubble collapse, the emitted shock wave attenuates rapidly with increasing propagation distance, and the attenuation of shock pressure follows the relationship: f=163.17er/0.21+18.11. When the emitted shock wave propagates around the spherical surface, the shock front remains consistently perpendicular to the spherical surface, while a region of high wall pressure is generated at the intersection of the incident and reflected waves. Notably, the peak value of this wall pressure exhibits significant sensitivity to the initial bubble–wall distance.