三角波形激光脉冲在液体中致声的特性分析

为了研究激光脉冲波形对其在液体中致声特性的影响,基于激光致声的热膨胀机制机理,采用理论推导和数值仿真的方法,对三角波形激光脉冲激发声波的特性进行了分析。首先阐述了激光与液体媒质通过热膨胀机制作用激发平面光声源的理论;推导了激光脉冲为三角波形时在约束边界和自由边界下产生声脉冲的解析解,并通过仿真得到了声脉冲剖面;然后通过模拟得到了不同边界下激发光声脉冲的波形;最后分别推导了约束边界和自由边界下的光声转换效率,分析了转换效率的影响因素,并对不同边界下的转换效率进行了求解和对比。结果表明,该研究对激光致声技术的工程应用具有理论指导意义。

Analysis of Characteristic of Acoustic Waves Induced by a Triangular Laser Pulse

The theory of thermoelastic mechanism for generation of a plane acoustic source by a laser pulse in liquid is elaborated firstly. The analytic solutions of the acoustic pulses induced by laser pulses under the condition of rigid interface and free surface are deduced when the laser waveform is triangular, and the photoacoustic pulse sections are obtained through emulation. And then the photoacoustic pulse waveform is simulated. At last, the laser-acoustic conversion efficiency and its influencing factors are analyzed, and the conversion efficiency under the condition of rigid interface and free surface are solved and compared.