充液管道管口噪声的流固耦合效应数值模拟研究

Fluid-solid-acoustic interaction in the liquid-filled duct is a typical problem in ship and underwater vehicle industrial applications, which is also a great challenge for theoretical acoustics. Existing analysis methods on the duct and plate vibro-acoustics in liquid-filled ducts were almost based on pure analytical methods or analytical-numerical methods, where the fluid dynamics or effects were governed by linear, inviscid and irrotational flow equations or described by some approximate models. Thus, some linkages in the fluid-solid-acoustic interactions have been ignored or simplified. This project is proposed to use the state-of-the-art computational fluid dynamics (CFD) progresses, to develop numerical simulation methods with high-order accuracy for fluid field and acoustic field, and with fluid-structure interaction (FSI) base on modal methods for structure. Aiming to the model of pipe opening, build a numerical platform for the complete fluid-solid-acoustic interactions base on a novel strategy, which consider the acoustic process in fluid domain and solid domain. The coupling program on CFD, CAA and vibro-acoustics will be developed. Utilizing the numerical platform, the generation and propagation of the fluid-borne noise in the pipe opening considering structural feedback will be investigated. The vibration and structure-borne noise of the baffled elastic panel with fluid-loads and vibro-acoustic couple will be studied. The qualitative and quantitative effect of the fluid-solid interaction to the sound propagation and radiation in the pipe opening system will be analyzed, to give some general conclusions for the prediction and control of the noise of pipe opening.

充液管道中的流-固-声相互作用，是船舶和水下航行体相关工程中的典型问题，也是声学学科在应用中面临的挑战之一。现有的液体管道声传播及板结构噪声的分析方法多建立在理论方法或半解析半数值方法基础上，其中流体动力学作用常用线性、无黏无旋的方程或理论近似模型描述，流-固-声耦合的一些环节被忽略或简化。本项目拟利用最新的计算流体力学发展成果，发展基于高精度流场和流噪声数值模拟、基于结构模态法的静弹性流固耦合模拟，针对简化的管口模型，建立在流体域与固体域均考虑声学过程的流-固-声耦合全链条数值模拟新策略，并开发整合计算流体力学、计算气动声学和声振耦合模块的耦合程序。利用所发展的数值分析平台，研究考虑结构对流体反作用的管口射流流噪声声源和声传播特性；研究流体力加载作用下、与流噪声耦合的障板振动和噪声特性；分析流固耦合效应对管口系统声传播和声辐射的定性和定量影响，为更精确预报和控制管口噪声提供一般性结论。

本项目旨在针对典型的水下（或一般的不可压流动，低速气体流动）及管道流动中的噪声问题，建立流-固-声耦合数值模拟的数值方法，包括发展和完善其中各环节的数值方法，通过典型物理问题的模拟获得机理性认识。在计算流体力学、计算气动声学和声振耦合的最新发展水平和课题组积累的基础上，经自主开发程序及与商业软件的整合，建立了一类新型的流-固-声耦合全链条数值模拟平台。发展了新的高精度计算气动声学程序和基于浸入边界法的流-声、流-固耦合框架。通过较大数量的数值模拟验证和典型问题的应用算例，侧重研究了流-声单向作用、流→固→声作用和声-固耦合等一系列典型物理问题。此外，针对湍流噪声的基础问题，提出了“螺控声”理论框架，利用直接数值模拟分析其模态竞争和能量分配的物理机制，阐明螺度控制的作用。已发表SCI论文1篇，EI论文（AIAA paper）1篇，项目成果预计后续还有2篇SCI论文发表。本项目的实施和课题的进展，一方面为进一步的流-固-声耦合研究奠定了坚实的数值模拟工具基础，一方面得到了一系列机理研究结果。两方面均有较强的创新性，在相关的方向形成了新的生长点，具有重要的理论价值和工程意义。