圆柱-柔性板结构涡激振动的动力分叉数值研究

Numerical Study on Dynamic Bifurcation of Vortex-induced Vibration of a Circular Cylinder with Flexible Splitter Plate

基于商用软件COMSOL Multiphysics中的流固耦合模块,以固定的圆柱-柔性板结构的二维绕流模型为研究对象,对其在低雷诺数下的涡激振动行为进行数值模拟,分析柔性板在发生动力分叉时的流场特征以及柔性板的振幅与振频特征。结果表明,柔性板的动力分叉行为与来流雷诺数有关,在计算雷诺数范围内,柔性板存在静止和小幅值振动两种典型的分叉行为。静止情况下,板的偏转角随雷诺数的增大而增大;小幅值振动情况下,随着雷诺数增大,板的振动行为从等幅振动发展成拍频振动;继续增大雷诺数,柔性板的动力分叉行为消失。这进一步证实了柔性板涡激振动时的动力分叉行为同时取决于来流雷诺数及板的固有频率。

Based on the fluid-structure coupling module in the commercial software COMSOL Multiphysics,this paper takes the flow model of two-dimensional fixed cylindrical-flexible plate structure as the research object,and simulates its vortex vibration behavior at low Reynolds number.This paper mainly discusses the flow field characteristics of the flexible plate when the dynamic bifurcation occurs,as well as vibration characteristics of the flexible plate.The results show that the dynamic bifurcation behavior of flexible plates is related to the incoming Reynolds number.In the range of all calculated Reynolds numbers,two typical bifurcation behaviors of flexible plates are found(static and small amplitude vibration):Under the static dynamic bifurcation condition,the deflection angle of the plate increases with the increase of Reynolds number;under the dynamic bifurcation condition of small amplitude vibration,the vibration behavior of the plate develops from constant amplitude vibration to beat frequency vibration with the increase of Reynolds number;the dynamic bifurcation behavior of flexible plate is eliminated with further increase of Reynolds number.This study further confirms that the dynamic bifurcation behavior of a flexible plate depends on both the Reynolds number and the natural frequency of the plate.