非线性内波引起的浅海混响强度异常震荡

Singular reverberation intensity induced by moving nonlinear internal wave in shallow water waveguide

为了解决浅海环境中,海底混响和杂波对限制主动声呐探测性能的干扰,本文研究了浅海中移动的非线性孤子内波引起的海底杂波和海底混响强度的变化规律。针对收发合置的海底混响,本文以简正波混响模型为出发点,通过引入耦合矩阵的理论推导,表征了孤子内波对声场各模态间的能量交换,给出了孤子内波引起的海底杂波的物理机制,得到了震荡周期和内波的移动速度之间的关系式。仿真结果表明:非线性内波会导致强杂波,并引起杂波后的平均混响强度异常震荡。研究为识别内波导致的强杂波干扰、利用混响对孤子内波进行测距和测速提供了一种可行的理论机制。

In order to solve the interference of seabed reverberation and clutters on the detection performance of active sonar in shallow water,we studied the variation law of seabed clutters and seabed reverberation intensity caused by nonlinear soliton internal waves moving in shallow water.Aiming at the seabed reverberation combining transmitting and receiving,in this paper,the energy exchange between soliton internal waves and various modes of sound field is characterized by introducing the theoretical derivation of coupling matrix based on the normal mode reverberation model.The physical mechanism of submarine clutters caused by soliton internal waves is given,and the relationship between oscillation period and internal wave's moving speed is obtained.The simulation results show that nonlinear internal waves will lead to strong clutters and cause abnormal oscillation of average reverberation intensity after clutters.The research provides a feasible theoretical mechanism for identifying the strong clutter interference caused by internal waves and measuring the distance and velocity of soliton internal waves by reverberation.