复等效深度耦合简正波模型

为了考虑海底地形随距离变化的非水平分层介质中割线积分对声场的贡献,提出了复等效深度耦合简正波模型。该耦合简正波模型由介质运动方程和连续性方程推导得到了耦合微分方程组,此方程组满足海底地形随距离变化情况下的边界条件且仅包含一个耦合矩阵,并通过引入复等效深度理论处理连续谱和离散谱之间的相互耦合。仿真计算表明,复等效深度耦合简正波模型提高了波导简正波本征值位于割线枝点附近情况下声传播损失的计算精度,充分考虑了波导简正波、非波导简正波和割线积分对声场的贡献,可快速而准确地计算非水平分层介质中的声场。

A coupled-mode sound propagation model with complex effective depth

In order to consider the effect of branch line integral for acoustic field in a range-dependent waveguide with varying topography, a coupled-mode sound propagation model with complex effective depth is presented. The equations of motion and continuity are used to obtain the coupled equations, which satisfy correct boundary conditions in the waveguide with varying topography and contain one coupling matrix. Meanwhile, the couplings between discrete and continuous spectrums are dealt with based on complex effective depth theory. It is shown with numerical simulations that the accuracy of transmission loss is improved by the coupled mode model when eigenvalue of trapped mode is located on the neighbourhood of branch point. The acoustic field in a non-horizontally stratified waveguide can be calculated efficiently and accurately by this model, and the energies corresponding trapped modes, leaky modes and branch line integral can be considered adequately.