An experimental investigation on the ice-breaking phenomenon induced by the spark-generated bubble near a vertical plate

Abstract

The present work experimentally studied the coupled interaction between the fracture of an ice plate floating on the water surface, induced by the pulsation of a high-pressure bubble, and the associated deformation of a vertically submerged aluminum plate. The dynamic behaviors of bubbles and fractured ice were concurrently recorded using two high-speed cameras, and the plastic deformation of the aluminum plate was measured by an ultra-depth three-dimensional microscope. The results indicated that the jet direction of the collapsed bubble is heavily influenced by the position to generate the bubble due to the competing Bjerknes forces caused by various boundaries. There is also a significant discrepancy in the phenomena of bubble collapse near thin vs thick ice plates, attributed to the sudden alteration in boundary conditions caused by ice fracturing. Three distinct ice-breaking mechanisms, namely, the hogging moment, jet impact, and the secondary shock wave, were identified based on the types of loads, leading to the initial ice fractures. In general, it was observed that the efficiency of ice breaking improved with a decrease in the bubble–ice distance (γf) and an increase in the bubble–plate distance (γm). It was found that the contacting jet from an upwardly collapsed bubble is the most effective in breaking the thickest ice plates for γm>1.9. While the shock wave from a bubble collapsing near solid wall corners could fracture thick ice plates, the aluminum plate risked damage from jet impacts when γm was less than 0.6.