水下声信号激发表面波衰减系数测量

Measurement of Attenuation Coefficient Base on the Liquid Surface Wave Which Stimulate by Underwater Acoustic Signal

建立了一个简单,可行的光学系统用于探测低频水下声信号。激光斜射到有表面波存在水面时,观察到了清晰、稳定的衍射图样,发现衍射图样具有明显的非对称性;且这种非对称性具有普遍的适用性。理论上得到了衍射光场光强分布的解析表达式。结果表明,衍射图样的非对称性与液体表面波的衰减系数有关。根据提出的方法可实现液体表面波衰减系数的便捷测量;且结果是很准确的。

A measurement system is developed to detect the low-frequency underwater acoustic signal which modulated by the underwater acoustic signal. The clear and stable diffraction pattern is observed experimentally when the laser beam illuminates on the liquid surface, the diffraction pattern is asymmetric distribution. The ex- pressions which the diffraction intensity was derived theoretically. Results show that the asymmetry distribution of the diffraction pattern is related to the attenuation coefficient of liquid surface wave. According to the presented method which was measured the attenuation coefficient of liquid surface waves, and the result is accurate.