Mechanism of high velocity jet formation after a gas bubble collapse near the micro fiber immersed in a liquid

•Vapor bubble shrinking near the fiber immersed in a liquid results in jet formation.•Jet is formed due to spherical symmetry breaking and collapse of converged flow.•Jet velocity depends on microfiber thickness.•Proposed mechanism explains previous experiments.•In medical applications/laser surgery such jets can destroy pathological formations. Numerical simulations of the vapor bubble collapse near the micro fiber immersed in a subcooled liquid allow us to propose the mechanism of formation of high velocity liquid jet previously observed in experiments. It is shown that spherical symmetry breaking of the velocity field near the fiber creates axisymmetric radially converged water flow resulting in appearance of the cumulative jet. Numerical simulations demonstrate that physical mechanism of jet formation is mainly determined by bubble surface dynamic and is irrespective to the processes driving bubble shrinking. Dependency of the jet velocity on time as well as effect of fiber thickness and initial vapor bubble radius on jet intensity are studied. It is found that optimal fiber thickness at which the jet is the most powerful exists. This optimal value is not universal but depends on initial vapor bubble radius.