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声波在海底中的传播衰减规律是海洋声学中值得研究的课题。根据简正波理论推导了高声速海底表层声场垂直衰减系数的解析表达式,并给出了其理论上限。数值仿真与实验研究表明:对液态海底模型,海底表层声场垂直衰减系数与声波频率基本呈正比;对于特定频率,海水-海底声速比是影响垂直衰减系数的最主要因素,比值越小垂直衰减系数越大;对于斜率较大的楔形海底地形,且声源在深水区、接收点在浅水区的情形,垂直衰减系数会大大小于其理论上限。
The propagation of sound waves in the seabed is a subject deserved to be studied in marine acoustics. According to the theory of simple normal wave, the analytical expression of the vertical attenuation coefficient of the sound field in the high-sound-speed submarine surface is derived and its theoretical upper limit is given. Numerical simulations and experimental studies show that the vertical attenuation coefficient of seafloor sound field is basically proportional to the acoustic frequency for the liquid bottom model. The seawater-sea-floor sound velocity ratio is the most important factor affecting the vertical attenuation coefficient for a given frequency. The smaller the ratio, the lower the vertical attenuation coefficient The greater the slope of the wedge-shaped submarine topography, and the sound source in the deep water, the receiving point in the case of shallow water, the vertical attenuation coefficient will be much less than its theoretical limit.