浅海低频全波动混响水平纵相关模型

Horizontal-longitudinal coherence model of low-frequency reverberations in shallow water based on the full-wave reverberation theory

为研究浅海低频混响的水平相关特性,本文在浅海全波动混响理论的基础上,借鉴角度谱理论的混响垂直相关建模思想,结合海底反射系数的三参数模型,将混响平均强度的简正模态叠加的形式解转化为角度积分的解析解。利用海底反射系数的幅值参数和相移参数建立了浅海全波动混响水平纵相关模型。数值仿真表明:在混响噪声比足够高的条件下,混响水平纵相关随混响时间发生缓变,呈现稳定的亮暗相间的条纹;接收水听器水平距离在波长整数倍上会出现相关峰值,在半波长的位置出现相关谷值,与海上实验现象相同。

To examine the horizontal-longitudinal coherence of low-frequency reverberations in shallow water,a horizontal-longitudinal coherence model based on the full-wave reverberation theory is built using the bottom reflection loss parameter and phase-shift parameter.The model borrows the vertical coherence of reverberations in angular-spectrum theory,integrates the there-parameter model of the bottom reflection coefficient,and transforms the normal-mode superposition of the average reverberation intensity to the angular-integral formulation.Numerical simulation results show that the reverberation horizontal-longitudinal coherence is slowly varying with the reverberation time,such as stable light and dark stripes,on the condition that the reverberation/noise ratio is high enough.The correlation peak occurs if a receiver is set at the integral multiple wavelengths,whereas a correlation valley occurs if a receiver is placed at a half-wavelength.The same is true for experiments at sea.