Experimental investigation on the interaction of spark-generated array bubbles near a rigid wall

Abstract

This study experimentally investigates the interaction of an array of bubbles near a rigid wall. Three bubbles are simultaneously generated using underwater electric discharges, forming a linear alignment with approximately equal sizes. A high-speed camera was used to record the evolution of the bubbles, with the pressure sensors placed on the surface of the rigid wall to measure the pressure resulting from both the jet and collapse of the bubbles. The results demonstrate that the behavior of the array bubbles, including collapse, jetting, and coalescence, is significantly influenced by the dimensionless distances Ra = da/Rm and Rh = dh/Rm (where Rm is the maximum bubble radius, and da and dh represent the inter-bubble distance and bubble-wall distance, respectively). A series of experiments, designed with various Ra and Rh, were conducted to systematically investigate the behaviors of the bubbles and their resulting pressure characteristics on the central of the wall. This research aims to offer a practical reference for understanding interacting array bubbles and the potential pressure threats to nearby structures.