Investigations on the jets and shock waves of a cavitation bubble collapsing between a wall and a particle

The simultaneous presence of particles and cavitation bubbles has a deleterious effect on the performance and safety of hydraulic machinery through the generation of jets and shock waves. In the present paper, the mechanisms responsible for the generation and the evolution of jets and shock waves from a collapsing cavitation bubble situated between a spherical particle and a wall are simulated using a compressible two-phase flow solver. Specifically, the effects of bubble position on jet and shock wave behavior are qualitatively analyzed. The simulations and experiments reveal three typical cases of jet behavior: a jet toward the wall, double jets, and a jet toward the particle. Needle jets and shock waves are commonly generated by collisions of the bubble interface. In some cases, needle jets are associated with a high impact velocity. It is found that the smaller the distance between the particle and the wall, the higher the pressure generated by the jets and the shock waves on the wall.