Dynamics of a single cavitation bubble near a cylindrical rod

Abstract

In this study, we studied the dynamics of a laser-induced single cavitation bubble near a rigid cylindrical rod. We experimentally and numerically investigated the effects of the cylindrical rod on the dynamics of the growth and collapse of the single bubble at different relative wall distances. First, we performed the experiments using a high-speed camera to analyze the shape of the bubble collapse qualitatively. Second, we performed a numerical simulation using a fully compressible two-phase mixture model and an interface capturing scheme to analyze the dynamics of the single cavitation bubble. We analyzed different quantitative parameters, such as maximum velocity of the microjet and the pressure impact load for the bubble at various relative wall distances. The results showed that the bubble dynamics collapsing near the cylindrical rod differed significantly from the single bubble collapse near solid flat plates. A shape of mushroom can be formed during the collapse of the single bubble near the cylindrical rod at the smaller relative wall distances, such as γ = 0.3, 0.4, and 0.5. This mushroom-shaped bubble was not observed for the cases near the solid flat plates in the previous research or near the higher relative wall distances in our present results. In addition, our numerical results revealed that a mushroom-shaped bubble for the cases γ = 0.4, 0.5, and 0.7 may induce a lower jet impact load near the solid surface compared with the case γ = 1.0 with an oval-shaped bubble near the solid boundary.