有限水深环境圆柱壳声辐射及传播特性

Sound radiation and spread characteristics of cylindrical shell in finite depth water

采用虚源法建立了浅水环境中二维圆柱壳的振动声辐射数学物理模型,推导了浅水上下界面对柱壳声辐射的散射作用,利用柱函数转移公式推导了虚源和圆柱壳的互辐射阻抗矩阵,描述了不同虚像声场对本体圆柱壳的负载。利用典型圆柱壳参数和浅水参数初步计算了浅水对圆柱壳振动声辐射的影响规律及水深、潜深对声场分布和衰减特性的影响规律。研究结果表明:针对文中典型模型参数,圆柱壳没入水中深度超过0.5 m,其振动响应和表面声压与在无限水域中一致;水面和水底对圆柱壳辐射声的反射与本身辐射在有限水域内形成复杂驻波;有限水域的近场衰减特性与无限水域中的近场衰减特性基本一致;由于驻波的影响,远场声压衰减曲线相较无限水域的柱面波衰减曲线上下起伏6 dB左右,但总体衰减趋势基本一致。

A mathematical model is established, which describes vibration and radiation of 2-D cylindrical shell in shallow water, and the influence of the pressure release surface and the waterbed is taken into ac- count by Image Source Method （ISM）. The interaction of various image sources is described by impedance derived from cylindrical function transferring. The radiated sound distribution field of the cylindrical shell is numerically simulated with typical parameters of shell and water based on the physical mode. The results show that when the immerse depth of the upper surface of the shell with typical parameters in this paper beyond 0.5 m, the response of the shell is just the same as the case immersing in infinite water, and the attenuation of the sound pressure along the distance in nearby space of shallow water has the similar trends with whose behavior in infinite water; and the attenuation of sound pressure in the far-field differs from cylindrical wave attenuation in infinite water reaches up to 6 dB due to the standing wave caused by the water-surface and water-bed, while the trends of the attenuation behave similar.