Experimental study of the control of cavitation-induced erosion created by collapse of single bubbles using a micro structured riblet

Abstract

Cavitation can be formed on ship rudders, ship propellers and hydraulic system components and can induce erosion on solid surfaces. One of the remaining open questions in the study of the cavitation erosion is finding a method to control erosion generated by the collapse of single bubbles near a solid surface. In this study, we proposed a passive control method using a shark skin inspired micro structured riblet solid surface to control the dynamics of a single bubble collapse and the cavitation-induced erosion. We experimentally investigated the effects of a micro structured V-shaped riblets on the dynamics of a laser-generated single cavitation bubble. First, the dynamics of a single cavitation bubble near a smooth rigid surface is obtained at different relative wall distances. Second, the dynamics of a single cavitation bubble near a rigid surface covered by micro structured riblets are compared with our experiment on the smooth rigid surface for the relative wall distances. The results showed that the bubble dynamics collapsing near the riblet surface differed significantly from the single bubble collapse near the smooth surface. The interaction of microbubbles formed between the bubble and the riblet surface during the first collapse mitigated the momentum of the microjet. Furthermore, the riblet structure altered the bubble’s shape during its collapse and rebound process and significantly reduced the torus ring generated after the first and second collapses. The riblet structure also reduced the cavitation-induced erosion area on the rigid surface with the micro structured riblet.