水下强声波脉冲引发的空化气泡运动和声辐射

通过建立由等离子体声源、PCB压力传感器和高速相机等构成的实验测量系统,研究了强声波脉冲引发的空化气泡运动和二次声辐射。通过实验,观察到了强声波脉冲特有的波形结构,空化气泡的成长、膨胀和坍缩过程以及气泡坍缩时辐射的声信号。其次,利用Gilmore方程和Bernoulli方程,从理论上对空化气泡的运动和声辐射进行了数值模拟和分析。研究结果表明：（1）在强声波脉冲正压区的作用下,空化气泡将受到压缩并围绕＂准平衡态半径＂振荡;在强声波脉冲负压区的作用下,空化气泡将出现膨胀、坍缩和回弹的物理过程。（2）空化气泡坍缩时周期性辐射的声脉冲持续时间极短,具有＂冲击波＂的特点。

A study of cavitation bubble dynamics and sound emission induced by underwater intensive acoustic pulse

An experimental system including underwater plasma acoustic source,PCB pressure sensor and high speed camera was built up.The bubble dynamics induced by intensive acoustic pulse and its sound emission were studied.The typical waveform of the intensive acoustic pulse was captured,and the growing,expanding and collapsing process of the bubble and its emitted sound were observed.Theoretically,Gilmore equation and Bernoulli equation were used to simulate the bubble dynamics and sound emission,based on which the numerical calculation and analysis were performed.The results indicate that：（1）Bubble will be compressed and will oscillate around the＂quasi-equilibrium radius＂during the positive pressure phase of the incident pulse,and then the bubble will undergo the process of expanding,collapsing and rebounding during the negative pressure phase of the incident pulse;（2）The duration of the periodically radiated acoustic pulse of the collapsing bubble is very short,which exhibits the characteristic of a＂shock wave＂.