有限深度两层流体系统中运动点源生成的内波及其与自由面的相互作用

基于水波动力学势流理论,以二流体系统中点源运动为基本模型,采用Green函数法,研究了分层流体中内部扰动诱生的内波对自由面的影响,探讨对合成孔径雷达成像起重要作用的自由面辐散场的变化规律。研究表明:当上下层流体密度跃变较大、源接近密跃层且Froude数Fr接近内波模式的临界值Fr₂时,内波模式导致的自由面辐散场强度与表面波模式的贡献相当,两者具有强烈的耦合作用,理论分析与实验结果定性一致。

Suarface Effects of Internal Wave Generated by a Moving Source in a Two-Layer Fluid of Finite Depth

Based on the potential flow theory of water waves, the interaction mechanism between the free-surface and internal waves generated by a moving point source in the lower layer of a two-layer fluid was studied. By virtue of the method of Green. s function, the properties of the divergence field at the free surface were obtained, which plays an important role in the SAR image. It is shown that the coupling interaction between the surface-wave mode and internal-wave mode must be taken into account for the cases of large density difference between two layers, the source approaching to the pynocline and the total Froude number Fr close to the critical number Fr₂. The theoretical analysis is qualitatively consistent with the experimental results presented by Ma Hui-yang.