単一気泡のリバウンド挙動と衝撃波の伝播に関するモデリングと数値シミュレーション

抄録

Cavitation is a formation of bubbles in liquid with high-speed, where a phase transition from liquid phase to gas phase occurs when the pressure of the liquid is reduced to the saturated vapor pressure. The Rayleigh-Plesset equation is well known mathematical model of a spherical single cavitation bubble. However, there have not been proposed an appropriate mathematical model of such a single bubble including the shock wave phenomenon associated with the collapse of the bubble. In this study, we propose a coupled model of the Rayleigh-Plesset equation and the wave equation associated with pressure. In this model, these equations are combined by a bubble surface boundary condition, which is defined by solutions of the Rayleigh-Plesset equation. Further, by using our coupled model, we make a numerical test of the rebounding behavior of the single bubble in an ultrasonic field and the shock wave emission. As a results, we show that the shock wave phenomenon associated with the collapse of the bubble, namely, an intensive pressure on the bubble surface and the shock wave propagation are reproduced.