EXPERIMENTAL INVESTIGATION OF THE INFLUENCES OF THE SPHERICAL PARTICLE ON THE JET FORMATION OF THE CAVITATION BUBBLE NEAR THE SOLID BOUNDARY¹⁾

Based on a high-speed camera system, this paper investigates the jet formation of the cavitation bubble during its collapse between the solid boundary and the spherical particle. During the experiment, the two parameters (the non-dimensional distance between the bubble and the particle, and the non-dimensional distance between the bubble and the solid boundary) are carefully controlled. Through the analysis of the photos and the data collected during the cavitation dynamic oscillations by the high-speed camera, it is found that the non-dimensional parameter \alpha (the ratio between the aforementioned two distances, representing the relative position of the bubble near the solid boundary and the particle) is a key influencing factor determining the phenomenon, in the quantitative and qualitative analyses. Our analysis reveals that: (1) unlike the case without the particle, the presence of the particle could alter the jet direction significantly during the bubble collapse and the alternation of the jet increases with the decrease of \alpha; (2) for small \alpha, the bubble makes a significant movement along the particle interfaces.