抖振问题中的结构锁频现象是一个非常引人瞩目的课题，这不仅因为锁频的奇特性，更在于振动幅值在锁频区域将达到峰值，极易造成结构的破坏。绝大部分学者将锁频现象归结为共振问题。然而，共振是如何导致锁频的？为何锁频也会在共振区之外出现？项目组近期研究发现，分离流中的锁频现象与结构模态和流动模态的耦合效应密切相关。本项目研究以提取不稳定的流场结构和非定常气动力特征为突破口，构建非定常分离流的降阶模型，通过状态空间耦合结构和流体运动方程，建立自诱型抖振的流固耦合数学模型。以绕弹性支撑的圆柱、大迎角翼型抖振和跨声速翼型抖振为研究对象，通过特征分析方法，结合CFD/CSD仿真方法，揭示抖振问题中结构锁频现象的诱发机理，并研究相关参数对锁频范围和特征的影响规律。最后，通过风洞实验对研究结论进行验证。研究成果可为航空工程等领域解决锁频状态下的破坏性抖振问题提供理论依据和实践指导。

The structural lock-in is a remarkable phenomenon in buffeting problems. It is not only due to its peculiarity, but also due to the vibration amplitude will achieve a peak value in lock-in state, which will induce the structural failure. Most of the researchers pin the mechanism of lock-in phenomenon on resonance. However, how resonance induces the structural frequency lock-in? Why lock-in phenomena will appear out of the resonance region? From our recent research, the lock-in phenomena in the separated flow is closely related to the interaction between the fluid mode and the structural mode. .. In this project, we will construct the unstable fluid mode and reduced the order of aerodynamic model by POD method or system identification methods firstly. Then by coupling the fluid model and structural model in state-space, the analytical fluid-structure interaction model of the buffeting problem in unstable flow field is established. .. The vortex induced vibration, buffeting at high angle of attack and transonic buffeting will be researched. By solving the eigenvalue problem, combining with the CFD/CSD time simulation results, the mechanics of lock-in phenomenon will be discovered. The lock-in region and the characteristics will then be studied. Lastly, the research conclusion will be validated by the wind tunnel experiments... The research achievement of the project is very important on both theoretical value and applied value for solving structural buffering problem in aeronautic engineering, civil engineering, nucleus engineering and ocean engineering, et al.