Influence of bubble-particle distance on the dynamic behaviors of a cavitation bubble near a particle

Cavitation and silt-erosion often co-exist, causing severe damage on fluid machinery. In this paper, the dynamic behavior of a cavitation bubble near a fixed spherical particle is numerically studied, with the focus on the influence of the stand-off distance γ on the bubble collapse morphology, micro-jet velocities and pressure on the particle. With the increase in the value of γ, the bubble profile in the collapse stage exhibits three distinct characteristics: Mushroom-shaped, pear-shaped and spherical-shaped, and the corresponding micro-jets are identified as contact jet, non-contact jet, and long-distance jet. All studied distances can be categorized into three ranges, and the typical cases in each range are demonstrated. The maximum jet velocity V_max and the maximum pressure difference between the upper and the bottom of the particle Δp_max show the highest peak at γ = 0.9, with V_max up to 180 m/s and Δp_max up to 10.8 MPa.