宽频复杂激励下双层圆柱壳透射噪声、辐射噪声耦合机理研究

With the application of quiet power equipment, buoyant raft and air-pocket vibration isolators, the hull structures' sound radiation is effectively reduced. Lots of engineers and scholars pay attention to transmission noise which is generated by higher airborne-sound equipment.The radiation noise and transmission noise are always separately analyzed in this research realm,the influence of low-frequency vibrating shell on transmission noise is ignorced.Starting with the coupling phenomenon of cabin air-borne transmission noise and structure radiation noise,the transmission noise analysis model’s drawback of constant incidence interface is overcame.The coupling mechanisms of double cylindrical shells' transmission noise and radiation noise under broadband complex motivation are explored during the following three processes. 1). Based on elastic wave theory, the sound transmission numerical model of high-frequency airborne noise incident into low-frequency vibrating shell is established. Conbination of differential quadrature element method and dual boundary integral equation method,the double cylinderical shells’s underwater coupling sound field under broadband complex motivation is calculated. 2).The influences of parameters on the coupling characteristics of double shells’ transmission and radiation noise are explored, such as low-frequency vibrating fluid-solid boundary condition, mechanical motivation, airborne noise intensity, frequency bandwidth and hull structure parameters. 3).The quantitative magnitude relation and control frequency band of double shells’ transmission and radiation noise are researched through model experiment,and the validity of numerical model is also verified.

随着安静型动力设备、舱筏及气囊隔振的应用，艇体机械噪声得到了有效的抑制，高空气噪声设备诱发的透射噪声引起了广泛关注。目前该领域大多将透射噪声与辐射噪声问题孤立地进行分析，忽略了低频振动壳体对气动噪声透射特性的影响。本研究从双层圆柱壳舱室噪声透射与结构声辐射耦合现象入手，针对以往噪声透射分析模型假定入射声波作用界面固定不变的缺陷，探索宽频复杂激励下双壳透射噪声与辐射噪声的耦合作用机理，主要研究内容包括：1）、基于弹性波动理论，建立双壳低频振动的流固耦合物面处高频空气噪声透射数学模型，结合微分求积法、双重边界元法计算宽频复杂激励下双壳水下耦合声场；2）、分析壳体机械激励度、空气噪声强度及频率特性、壳体结构参数、声学覆盖层参数对双壳透射噪声与辐射噪声耦合特性的影响规律；3）、通过模型实验定量分析双壳透射噪声、辐射噪声的幅值关系及主要控制频带，验证本研究建立数值模型有效性。

随着安静型动力设备、舱筏及气囊隔振的应用，艇体机械噪声得到了有效的抑制，高空气噪声设备诱发的透射噪声引起了广泛关注。目前该领域大多将透射噪声与辐射噪声问题孤立地进行分析，忽略了低频振动壳体对气动噪声透射特性的影响。本研究从双层圆柱壳舱室噪声透射与结构声辐射耦合现象入手，针对以往噪声透射分析模型假定入射声波作用界面固定不变的缺陷，基于波动理论建立了宽频复杂激励下双壳低频振动的流固耦合物面处高频空气噪声透射数学模型，结合微分求积法、双重边界元法计算宽频复杂激励下双壳透射噪声、结构辐射噪声耦合声场。形成了一套双壳结构透射噪声、辐射噪声水下耦合声场贡献量试验分析方法，通过设置多种声源/力幅激励工况定量分析双壳透射噪声、辐射噪声的幅值关系及主要控制频带，同时验证本文理论分析的有效性。旨在揭示双壳透射噪声与辐射噪声的耦合作用机理。取得的主要结论及进展情况如下：1）建立了双层圆柱壳在内部舱室噪声及机械激励力联合作用下的壳体波动方程，探明了复杂宽频激励下的双壳水下声场耦合机理；2）定量分析了壳体机械激励度、空气噪声强度及频率特性、壳体结构参数、声学覆盖层参数对双壳透射噪声与辐射噪声耦合特性的影响规律，提供一种快速多极子双重边界元计算方法及计算程序；3）形成了双壳透射噪声与辐射噪声耦合声场实验测试方法，通过EMD经验模态分解法定量分析二者的量级关系及主要控制频带，并为本研究的数值结果提供实验验证，为工程应用提供支撑。