有限浸深流场中圆柱壳结构的声振模型及特性研究

The finitely submerged status includes two cases: First, the depth of the submerged structure under the free surface is finite. Second, the structure floats on the free surface. In these two cases, the boundedness of the fluid sound field and the characteristics of the sound field on the free surface must be considered. In order to break through the key method studying the vibra-acoustics coupling between the free surface with sound medium and the elastic cylinder shell, and to discover the influence law of the free surface to the vibra-acoustics performance of the finitely submerged cylinder shell, the vibra-acoustics model of the cylinder shell coupled with external fluid under the finitely submerged status is planned to built. This research result will be of important academic significance and national defense application value. The main contents of this project are as follows: Research on the vibra-acoustics coupling mechanism and the physical model of the cylinder shell under the finitely submerged status. Research on the characteristics of the radiated sound field and the vibration energy flow of the finitely submerged cylinder shell. Analysis on the vibra-acoustics sensitivity of the parameters and research on the control method of sound and vibration produced by the coupling system. Measurement of the model experiment and comparative analysis between the experiment results and the calculation results. Relation research on the vibra-acoustics performance of cylinder shells in floating status, finitely submerged status and infinitely submerged status. This project is the melioration and extension of the existing research work by the applicant and his project team. Its unique and creative points lie in two points. In the view of theoretical point, the vibra-aoustics model of the cylinder shells under the finitely submerged status is built, which perfects the theoretical system of vibra-acoustics of submerged cylindrical shell with different depth. From practical point, the research method and control technique on the vibra-acoustics performance of the finitely submerged cylinder shells that considered the influence of free surface are put forward, which offers theoretical foundation for improving the vibra-acoustics performance of the coupling system of the finitely submerged cylinder shell.

有限浸深圆柱壳包括其悬浮于自由液面下有限深度(有限潜深)，或者结构漂浮于自由液面上，此时必须考虑声场的有界性和自由液面处的声场属性。针对前期无限声场假设的不足，拟突破自由液面及有限声介质与圆柱壳声振耦合的关键技术，建立有限浸深圆柱壳耦合系统的声振模型，揭示自由液面和有界声场对声振性能的影响规律。研究结果具有重要的学术意义与国防应用价值。 主要内容包括：有限浸深圆柱壳的声振耦合物理模型及机理研究；有限浸深圆柱壳辐射声场与振动能量流的特性研究；参数的声振灵敏度分析及声振控制方法研究；模型实验及结果对比研究；圆柱壳在水面浮态、有限潜深状态、无限域流场状态下声振性能的关系研究。 本项目是申请者已有研究的完善、深入和发展，其特色和创新之处在于理论上建立有限浸深圆柱壳结构的振动与声学模型，完善不同潜深下圆柱壳声振研究的理论体系；在应用上提出有自由液面影响的有限浸深圆柱壳声振性能的研究方法与控制技术。

现有的关于水中圆柱壳声振特性的研究大多假设结构浸没在理想的无限声介质中，而在工程应用中，流域会受到自由液面、水底、岸壁等边界的限制，且流体边界会对声波产生反射作用，进而影响流场中结构的声振特性。目前，关于声边界约束下水中圆柱壳声振特性的研究工作尚待深入，本项目结合波传播方法和虚源法分析了声边界（如自由液面、刚性底面及组合边界等）约束下水中有限长圆柱壳的声振特性，并从模态附连水质量的角度解释了声边界的影响机理，为工程应用提供了理论参考。. 对有限潜深状态下圆柱壳-声场耦合系统，研究结构的自由振动特性及其在动载荷作用下的振动和声辐射特性，并对浅水域中圆柱壳的振动特性进行了实验测量研究展开了试验模型设计研究和实验方案设计，完成的研究内容为：（1）有限潜深状态圆柱壳-声场耦合系统的耦合声振模型研究；（2）有限潜深状态下圆柱壳的声振特性研究；（3）浮态圆柱壳的声振特性研究；（4）结构声振特性对浸没深度的灵敏性研究。. 获得的主要研究成果如下；（1）从声固耦合角度提出了模态附连水质量的概念；（2）建立了有限潜深状态下有限长圆柱壳-声场耦合系统的耦合振动模型；（3）开展了耦合系统的振动与声辐射特性研究；（4）建立了浮态有限长圆柱壳-声场的耦合振动模型；（5）探讨了浮态圆柱壳的振动与声辐射特性；（6）培养了7名博士研究生和2名硕士研究生。. 本项目是申请者即课题组已有研究工作的完善、深入和发展，其特色和创新之处是探究了典型声学边界对水下圆柱壳声振特性的影响机理，为更好地预报服役状态下的水下航行器的声振特性和结构的声学优化设计提供了理论基础。