海底表层声场垂直衰减分析

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。 

Analysis on the surface-seafloor acoustic vertical attenuation

The rule of acoustic attenuation when sound propagates in the marine seafloor is worthy of research.As for the high-speed seafloor situation,by using the normal-mode theory,the surface-seafloor acoustic vertical attenuation in shallow water is investigated,and the analytic expression,as well as its upper bound,is derived.The analysis of the simulation and experiment results shows that,as for the high-speed fluid seafloor model,the vertical attenuation is proportional to sound frequency on the whole.At a certain frequency,the water-seafloor sound speed ratio n has a major impact on the vertical attenuation.The smaller the value of n,the greater the vertical attenuation.For the scenario of a large-slope wedge topography with a sound source in the deep-water area,receivers in the shallow-water area,the vertical attenuation is significantly less than its theoretical upper bound.