水下低频振荡涡流场声散射调制机理与特性研究  

Mechanism and characteristics of sound scattering modulation by underwater low frequency oscillating vortex flow field

作　　者：荆晨轩 时胜国[1,2,3] 杨德森 张姜怡[1,2,3] 李松 Jing Chen-Xuan;Shi Sheng-Guo;Yang De-Sen;Zhang Jiang-Yi;Li Song(College of Underwater Acoustic Engineering,Harbin Engineering University,Harbin 150001,China;Acoustic Science and Technology Laboratory,Harbin Engineering University,Harbin 150001,China;Key Laboratory of Marine Information Acquisition and Security,Harbin Engineering University,Harbin 150001,China)

机构地区：[1]哈尔滨工程大学水声工程学院,哈尔滨150001 [2]哈尔滨工程大学,水声技术重点实验室,哈尔滨150001 [3]哈尔滨工程大学,海洋信息获取与安全工信部重点实验室,哈尔滨150001

出　　处：《物理学报》2023年第1期202-216,共15页Acta Physica Sinica

基　　金：国防基础科学研究计划(批准号:JCKYS2022604SSJS006);中央高校基本科研业务费专项资金(批准号:3072021CFT0501);声纳技术重点实验室(批准号:2021-JCJQ-LB-031/05)资助的课题。

摘　　要：水下涡流场对声波的散射问题是声波在复杂流场中传播的基本问题,在水下目标探测和流场声成像领域具有重要意义.针对水下低频振荡涡流场声散射调制问题建立了理论分析模型与数值计算方法,探究了其声散射调制声场的产生机理与时空频特性.首先,基于运动介质的波动方程,通过引入势函数将波动方程分解为流声耦合项和非耦合项,并对流声耦合项进行频域分析处理,揭示了水下振荡涡流场的声散射调制机理;其次,采用间断伽辽金数值方法对水下低频振荡涡流场中声传播过程进行了数值模拟,分析了低马赫数条件下,不同入射声波频率、涡流场的振荡频率和涡核尺度对涡流场声散射调制声场时空频特性的影响规律,并结合理论分析模型对其特性进行了解释.研究表明:低马赫数下,振荡涡流场对声波的散射可产生包含涡流场振荡频率双边带调制谐波的散射调制声场,且随着入射声波频率、涡核尺度的增大,散射调制声场强度增强,总散射声场空间分布具有对称性和明显主瓣,且主瓣方位角趋近于入射波传播方向;在频率比远大于1条件下,涡流场振荡频率对散射调制声场强度影响较小.The scattering of sound waves by underwater vortex flow filed is the basic problem of sound waves propagating in complex flow fields,which has important significance in implementing underwater target detection and sound imaging of flow field.The theoretical analysis model and numerical calculation method are established for the problem of sound scattering modulation in underwater low frequency oscillating vortex flow fields,and the generation mechanism and time frequency and space characteristics of the scattering modulation sound field are explored.Firstly,based on the wave equation of the moving medium,in the first-order approximation the wave equation is decomposed into the flow-sound coupling term and the non flow-sound coupling term by introducing a potential function,and the flow-sound coupling term is analyzed in the frequency domain,revealing the underwater oscillating vortex flow field.Secondly,the discontinuous Galerkin numerical calculation method is used to solve the wave equation of the moving medium,and the sound propagation process in the underwater low frequency oscillating vortex flow field is numerically simulated.Under the condition of low Mach number,the effects of incident sound frequency,the oscillation frequency of the vortex flow field,and the scale of the vortex core on the time-frequency and space characteristics of the scattering modulating sound fields of vortex flow field are analyzed,and theoretical analysis model is used to explain the characteristics.The research results show that under the condition of low Mach number,the scattering of sound wave by oscillating vortex flow field can produce a scattering modulated sound field containing the harmonic of oscillating frequency side frequency modulation.The amplitude of the scattered sound pressure changes periodically with time,and the forward scattering is much stronger than the backward scattering.The fundamental frequency scattering modulation is much stronger than the frequency doubling scattering modulation.With the increase of t

关 键 词：流声耦合 振荡涡流场 声散射调制 

分 类 号：TB56[交通运输工程—水声工程]