Migration orientation of the laser-induced cavitation bubble near a vertically rigid boundary and free surface

We studied the migration of a laser-induced cavitation bubble with the coupling of a vertical rigid boundary and free surface. We used a high-speed camera and particle imaging velocimetry to obtain and analyze the experimental data on the velocity distribution at the bubble surface, bubble migration, and the surrounding flow field. The results revealed that when the bubble was near the single boundary, the migration orientation was pointing toward the rigid boundary or away from the free surface. When the bubble was simultaneously near the two boundaries, the migration orientation deviated from the vertical direction and formed an angle. Subsequently, based on the Kelvin impulse model, the quantitative correlation between the migration angle and the stand-off distance was obtained, thereby predicting the migration orientation.