平板断面风致振动的流场驱动机理分析  

Flow Field Mechanism of Flutter of Plate Section

作　　者：刘祖军[1,2] 贾明晓[1] 杨詠昕[2] 

机构地区：[1]华北水利水电学院土木与交通学院,河南郑州450011 [2]同济大学桥梁工程系,上海200092

出　　处：《中国公路学报》2012年第4期75-82,共8页China Journal of Highway and Transport

基　　金：国家自然科学基金重大研究计划项目(90715039)

摘　　要：应用粒子图像测速技术分析了平板断面颤振过程中尾部旋涡变化过程,采用相位平均的方法研究模型周期性振动与旋涡规律性演化之间的关系。当风速低于颤振临界风速时模型尾部旋涡尺度较小,结构振动幅度较小,当风速接近颤振临界风速时尾部旋涡经历了能量从小涡向大涡的传递过程后由能量较大的旋涡控制结构振动,结构振幅明显增加,直到模型振动发散。结合计算流体动力学的数值模拟方法获得颤振时刻模型表面的压力场,采用本征正交分解技术分析模型表面压力的模态特征函数,并根据分析结果对模型表面进行合理分区,利用分块分析的思想研究颤振过程中气流能量输入特点。结果表明:在颤振过程中模型表面波动压力的主控成分向迎风端风嘴漂移;主控波动压力的漂移造成模型通过迎风端风嘴从气流中吸收大量的能量,在一个完整振动周期内,气流输入到振动系统的能量不断增加,而造成结构稳定性的丧失。The process of the rear vortex changing during the flutter of plate section was tested by particle image veloeimetry technique. The relation between periodic vibration and vortex evolution law was studied using the method of phase-average. When the wind speed was below the critical flutter wind speed, the scale of rear vortex and the structural vibration amplitude were small, and when the wind speed was close to the critical flutter wind speed, the vibration of structure was controlled by the vortex with larger energy after the energy was transmitted from small to large eddy, and the structural vibration amplitude increased significantly, until the model vibration diverged. The pressure of model surface was obtained by the method of CFD numerical simulation, and model surface pressure mode characteristic function was got using proper orthogonal decomposition （POD） technique. According to the result of POD analysis, reasonable partition of the model surface was made. The features of energy input during the flutter were researched by adopting block analysis. The results show that the main control component of the model surface pressure fluctuations moves to the windward side nozzle during the flutter, which has made the model absorb a lot of energy through the windward side nozzle from air, and in a complete vibration cycle, the energy input to the vibration system increases resulting in the loss of structural stability.

关 键 词：桥梁工程 颤振 粒子图像测速 流场机理 平板断面 本征正交分解 分块分析 

分 类 号：U441.3[建筑科学—桥梁与隧道工程]