高雷诺数范围内不同形状柱体流致振动特性研究

摘要

流致振动是自然界和工程领域中普遍存在的一种流固耦合现象，其流固耦合过程非常复杂，涉及许多科学上的难题，一直是国际前沿研究热点之一。针对不同截面形状柱体的流致振动进行数值计算，研究高雷诺数范围内（30000≤Re≤110000）柱体流致振动特性，分析柱体振幅、频率和尾迹旋涡形态。结果表明，粗糙表面圆柱和类梯形柱Ⅰ的的流致振动响应强于其他形状柱体，最大振幅达到3．5D。圆柱、方柱、三角柱和类梯形柱Ⅰ的流致振动随来流速度变化均观察到明显的涡致振动初始分支、上部分支和驰振。类梯形柱Ⅱ出现高频低幅振动，未观察到明显的振动分支。另外，柱体流致振动振幅和频率与尾迹旋涡形态紧密相关，在不同的振动分支，尾迹呈现出不同的旋涡形态。%Flow-induced motion (FIM) is widely existing in the nature and engineering applications.The interactions between structure and flow are often very complex and the FIM is one of the research focuses in the fluid-structure interaction dynamics.In the present study,FIMof cylinders with different cross sections was numerically studied in the flow field with high Reynolds number range of 30000 ≤ Re ≤ 110000.The amplitude,frequency,and vortex patterns of each cylinder were examined.The results indicate that the amplitudes of the circular cylinder with rough surface and the quasi-trapezoid cylinderⅠare higher than others,and the maximum amplitude of 3.5 times of diameters is reached.The initial branch of VIV (vortex-induced vibration),the upper branch of VIV and galloping are correctly predicted in the oscillations of the circular cylinder,square cylinder,triangular prism,and quasi-trapezoid cylinder Ⅰ. FIMwith high frequency and small amplitude is achieved for the quasi-trapezoid cylinder Ⅱ,but no FIM branch can be observed.In addition,the vortex pattern of cylinder is closely related with the amplitude and frequecy responses,and the vortex pattern is stable when the cylinder is in one branch.