近水面有限长谐振动圆柱的远场声学模型研究  

Analysis of Far-field Acoustic Model for a Finite Harmonic Vibrating Cylinder near Free Surface

作　　者：聂睿 李孟捷 辛子豪 高晟馨 NIE Rui;LI Mengjie;XIN Zihao;GAO Shengxin(No.710 R&D Institute,CSSC,Yichang 44300,China;Qingjiang Innovation Center,Wuhan 430076,China)

机构地区：[1]中国船舶集团有限公司第七一〇研究所,湖北宜昌443003 [2]清江创新中心,湖北武汉430076

出　　处：《数字海洋与水下攻防》2023年第3期338-345,共8页Digital Ocean & Underwater Warfare

摘　　要：提出了求解近水面有限长谐振动圆柱远场声学特性的解析方法。首先,基于镜像原理,以假定虚源模拟自由液面影响;再结合Graf加法定理,将虚、实源各声压项进行合并;声压转换到波数域后,将得到其简洁显示表达式;最后,重要指标——远场辐射声压则利用稳相法进行求取。针对不同声学成分的分类形式,建立了对应计算模型,模型可用于深入研究自由液面影响及结构表面互散射机理。研究结果表明:自由液面的影响可归纳总结为类偶极子效应,且该效应对辐射声与散射声的计算结果均有显著影响,但二者除相似传播规律外还存在不可忽视的相位差;散射声压随散射次数增大将以固定倍率衰减,且衰减速率与圆柱壳浸没深度成正比,但与壳体表面谐振动激励频率成反比。In this paper,an analytical method is proposed to study the far-field acoustic characteristics of a finite harmonic vibrating cylinder near free surface.Firstly,based on image method,the influence of free liquid level is taken into account with a hypothetical virtual source.Then,combined with Graf′s addition theorem,the sound pressure items of virtual and real sources are combined and converted into wavenumber domain to obtain a simple expression of sound pressure.Finally,the important index,far-field radiated sound pressure,is obtained by the method of stationary phase.Two kinds of mathematical physical models are established to deeply research the mechanism of acoustic scattering between the free surface and the structural surface.The results show that the influence of free liquid level can be summarized as acoustic dipole,which has significant influence on the calculated results of radiated and scattered sound,but there are phase differences that can not be ignored except for similar propagation laws.The scattered sound pressure decreases at a fixed rate with increasing number of times,and the attenuation rate is proportional to the submergence depth of the cylindrical shell,but inversely proportional to the excitation frequency of the resonance vibration on the shell surface.

关 键 词：自由液面 镜像原理 Graf加法定理 稳相法 

分 类 号：U663.2[交通运输工程—船舶及航道工程]