圆截面高柔结构因大幅涡振而发生破坏的案例屡见不鲜。既有研究对此类结构的涡振不稳定机制和负气动刚度的认识存在不足，可能使设计风荷载偏于危险。本申请项目以典型圆截面高柔结构（烟囱）为对象，进行刚性测压模型、多自由度气弹模型和连续壳体气弹模型相结合的风洞试验。通过刚性模型试验实现雷诺数效应模拟，将模拟方法应用于气弹模型。对气弹模型涡振位移和风压进行同步测量，通过涡振过程中涡脱频率和体系振动频率的关系来对比分析气动刚度的变化规律。结合非线性随机振动理论，基于气弹模型涡振响应特点及风压与位移响应互制关系的分析，揭示涡振不稳定性的根本原因。进而研究高柔烟囱在湍流场中涡激共振的激发机制和不稳定机制，及发生共振后的响应水平。最终提出兼顾气动刚度和涡振不稳定性的共振响应评估模型，在此基础上建立涡振等效风荷载计算方法。该研究可为此类结构(普通排气烟囱、天阳能烟囱、电视塔、化工塔)的抗风设计提供参考。

High flexible structures with circular section are frequently damaged by violent vortex-induced vibration (VIV) or resonance. Existing studies on the mechanism of unstable VIV, the level of VIV response, as well as equivalent load evaluation method are still insufficient and not thorough. The proposed project will employ three kinds of wind tunnel test, i.e., pressure measuring test by rigidity model, MDOF aero-elastic model test, and continuous housing aero-elastic model test. The rigidity model test will be used to simulate Reynolds number effect. The simulation method will then be applied to aero-elastic model test. The VIV displacement and wind pressure of aero-elastic model test will be measured simultaneously. The aerodynamic stiffness will be determined through the wind pressure of VIV and the system vibration frequency respectively. On the basis of vortex-induced vibration characteristic of VIV response and the relationship between wind pressures and displacement response, the reason for unstable vortex-induced vibration will be revealed. Subsequently, the mechanism of vortex-induced resonance excitation and the unstable mechanism of high flexible chimney will be investigated. Finally a semi-theoretical evaluation model of resonance response considering the aerodynamics stiffness and the instability of vortex-induced vibration will be established. And the method for calculating equivalent wind load of vortex-induced vibration will be proposed based on the model. This study will provide reference for the wind design of similar structures, such as chemical tower, TV tower with circular section, and solar energy chimney.