Jet dynamics of two successively generated bubbles adjacent to a particle

Continuously generated cavitation bubbles near particles are commonly encountered in particle-laden flows. This study employs a combined experimental and theoretical approach to systematically investigate the collapse dynamics of two tandem cavitation bubbles generated successively near a spherical particle, with the single-bubble–particle configuration serving as a comparison. Particular attention is paid to the effects of the generation sequence and the temporal interval between the two bubbles on jet properties, collapse morphology, and oscillation period. Our investigations show that: (1) The particle-directed jet observed in the single-bubble configuration is reorganized and evolves into distinct regimes involving directional deflection as well as jet enhancement and attenuation. (2) The contraction velocity of the bubble is reduced relative to the single-bubble configuration while its collapse asymmetry is amplified. (3) When the bubbles oscillate nearly synchronously, the longest period is observed. As the interval increases, the period first decreases and then increases, ultimately approaching that of the single-bubble configuration.