Roles of underwater explosion bubble accelerating expansion cut-off state in bubble dynamics and energy output

Abstract

The process of the bubble accelerating expansion plays an important role in underwater explosion, which determines the energy output and affects the bubble oscillation subsequently. In this paper, we treated the accelerating expansion cut-off state as the critical state and applied it to the division of the expansion work, energy output, and the initial condition for bubble oscillation. It found that the Rayleigh–Plesset equation was considered appropriate to investigate the roles of underwater explosion bubble accelerating expansion cut-off state compared to the Keller equation, volume acceleration model (VAM), and pu-diagram method, and that was verified by the experimental data. Furthermore, the influence of the critical state on the expansion work and energy distribution in the accelerating expansion process was clarified, the larger critical relative volume leads to higher expansion work efficiency and total expansion work, and the shorter critical time increases the portion of the shock wave energy in the expansion work. Our finding provides a method to study the initial condition for the bubble oscillation, and that has significance in the energy output research.