水下声辐射激励水表面声波的特征参数测量

Measurement for the characteristic parameters of the water surface acoustic wave induced by underwater acoustic radiation

采用激光干涉方法对水下声辐射激励水表面声波的特征参数频率和振幅进行了测量研究。从理论上对水表面声波激光相干测量信号的频谱构成进行了分析,在此基础上提出了水表面声波两个重要声学参数频率和振幅的解算方法,并通过数值仿真进行了验证。搭建了一套简单的激光干涉测量实验系统,对不同频率和声压激励的水表面声波进行了测量实验,验证了水表面声波频率和振幅解调方法的准确性。对水表面声波横向传播的振幅衰减现象进行了初步的实验研究,结果表明水表面声波的频率越高,振幅的横向衰减越快。研究表明激光相干检测方法能够准确地实现水表面声波振幅和频率的测量。

A laser interferometric method was used to determine the frequency and amplitude of water surface acoustic wave caused by an impinging acoustic radiation. The Fourier spectrum of water surface acoustic wave detection signal was studied. Then demodulation method upon the two important acoustic parameters frequency and amplitude of water surface acoustic wave was put forward based on spectrum analysis and demonstrated by a numerical simulation. A simple laser homodyne interferometer was built to detect the water surface acoustic waves. Detection experiments on water surface acoustic waves caused by different driving frequencies and different impinging acoustic pressures were conducted to verify the accuracy of this demodulation method. Preliminary detection experiments for transverse-propagation amplitude attenuation phenomenon of water surface acoustic wave show that as the frequency become higher, the amplitude decrease faster. This work proved that optical interferometric method could accurately determine the frequency and amplitude of water surface acoustic wave.