一种改进的水下光击穿声辐射计算方法

为了从理论上对光击穿辐射声波进行定量描述,在点源模型的基础上提出了一种改进的水下光击穿声辐射计算方法,利用波动方程和水下爆炸理论求解单点击穿的辐射声波,并推导了多点击穿的辐射声波。从理论上对多点击穿的声压波形、声源级、传播特性和指向性进行了定量计算,并通过实验数据对比进行了验证。结果表明,计算与实验结果是一致的,证明了该方法的正确性和有效性;当激光能量从0.1J增大至0.8J时,声源级从182.4dB增至188.2dB;当激光能量高于0.3J时,声源级变化很小;在垂直等离子柱体的方向上声波辐射最强,在等离子柱体方向辐射最弱,所有方向上声波强度均与距离的平方成反比。

Improved Method for Computing Underwater Acoustic Wave Induced by Laser Breakdown

In order to describe the acoustic wave quantitatively induced by laser breakdown, an improved method for computing underwater acoustic wave induced by laser breakdown is presented based on model of point source. Acoustic wave induced by laser breakdown with single and multiple regions is computed based on wave equation and underwater explosion theory. The characteristic of acoustic signal such as pressure waveform, sound source level, transmitting and directivity is analyzed quantitatively, and it is verified through the experiment data contrast. The results show that the coincidence between the computed and experimental data validates the theoretical model. As the laser energy increases from 0.1 J to 0.8 J, the sound source level increases from 182.4 dB to 188.2 dB, but when the laser energy exceeds 0.3 J, sound source changes slightly. The power of acoustic signal is highest in vertical direction of cylindrical region of plasma, and lowest in parallel direction. The intensity of acoustic wave makes an inverse proportion to the square of distance in all directions.