浅海质点振速场强度的深度分布特性

Depth Distribution Characteristics of Particle Velocity Field Intensity in Shallow Sea

质点振速场强度的深度分布特性对水声探测与估计具有重要影响.基于简正波非相干模态和变换到角度积分的近似条件,推导出质点振速的非相干简正波的角度积分形式,避免了本征值和本征函数的复杂计算,并揭示了质点振速强度在声源深度及对称深度具有显著变化特性的物理机理.数值结果表明:非相干质点振速的角度积分解析式可实现快速计算,并可较好地表征出质点振速强度的深度分布特性;同时,由于简正波模态幅度函数的叠加效应,垂直质点振速与水平质点振速的深度分布存在显著差异性;随后,以质点振速强度差为研究对象,分析了水平距离、声源频率、声速剖面及海水深度等参数对质点振速场强度的深度分布特性的影响.相关结论可为基于矢量场的被动目标深度估计提供理论依据.

The depth distribution characteristics of particle velocity field intensity have had a significant impact on underwater acoustic detection and estimation.In this paper,based on the approximate conditions of the incoherent normal modes sum transformation to angular integration,the angular integration form of incoherent normal modes of particle velocity was derived,which avoided the complex calculations of eigenvalues and eigenfunctions while revealing the physical mechanism behind the significant variations in particle velocity intensity with source depth and symmetrical depth.The numerical results demonstrate that the analytical expression of the angular integration of incoherent particle velocity can facilitate fast computation and effectively characterize the depth distribution characteristics of particle velocity intensity.Additionally,due to the superposition effect of the amplitude function of normal modes,there are notable differences in the depth distribution of vertical and horizontal particle velocity.Subsequently,focusing on the intensity difference of particle velocity,the study analyzed the effects of parameters such as horizontal distance,source frequency,sound speed profile,and water depth on the depth distribution characteristics of particle velocity field intensity.The findings provide a theoretical basis for passive target depth estimation based on vector fields.