Experimental and Numerical Analysis of Laser-Induced Cavitation Bubble Dynamics near Solid Boundaries in Viscous Fluids

The present study investigates the coupled effects of liquid viscosity and bubble–wall stand-off distance on near-wall cavitation bubble dynamics through combined experimental and numerical approaches. Although the influence of bubble–wall interaction has been extensively studied, the mechanism by which liquid viscosity modifies collapse behavior, rebound characteristics, migration, and energy dissipation remains insufficiently understood. We experimentally generate laser-induced cavitation bubbles in liquids with different viscosities, including water, 100 cSt silicone oil, and 350 cSt silicone oil, near a rigid wall, and capture their temporal evolution using high-speed imaging. We further perform axisymmetric Volume-of-Fluid (VOF) simulations using OpenFOAM to reveal the underlying physical mechanisms governing viscosity-dependent bubble collapse. A systematic investigation is conducted over different bubble-wall stand-off distances to quantify bubble lifetime, rebound strength, jet formation, migration, and energy dissipation. The first-cycle normalized collapse time does not exhibit a simple monotonic dependence on viscosity, whereas differences among the working fluids become more pronounced during rebound and subsequent oscillations. The higher-viscosity cases generally exhibit stronger damping, weaker rebound, reduced jet development, and smaller wall-directed migration. These findings indicate that near-wall bubble dynamics result from the combined effects of bubble–wall interaction, viscous resistance, and other fluid-dependent properties. Overall, the results provide new insights into the coupled influence of liquid viscosity and bubble–wall stand-off distance on cavitation bubble dynamics.