Numerical Simulation of Laser-Induced Bubble and Metal-Free Water Cannon

Abstract

Laser propulsion is expected to be the next-generation propulsion mechanism. In particular, metal-free water cannon realizes propulsion without a metallic target. In this study, we develop a numerical simulation code using the C-CUP (CIP and Combined, Unified Procedure) method to simulate a laser-induced bubble and a metal-free water cannon. We successfully reproduced the qualitative behavior of spouting water in a three-dimensional space when the metal-free water cannon is irradiated by laser. Furthermore, the calculated results for the time development of displacement of the metal-free water cannon agree qualitatively with the experimental results. We simulate the behavior of the laser-induced bubble and discovered that the bubble inhales the water once spouted out, and the target moves backward owing to the pressure difference generated by the bubble expansion as well as collapsing and inhaling actions. Furthermore, the laser-induced bubble repeats the expansion and collapse, and the target moves forward while it oscillates.