论文标题
在弹性安装的圆柱体的流动中，具有两级自动涡流诱导的振动的流动性
Three-Dimensionality in the flow of an elastically mounted circular cylinder with two-degree-of-freedom vortex-induced-vibrations
论文作者
论文摘要
该研究通过数值研究了流动的三维和两度富含（2 DOF）涡流诱导的振动（VIV）特性的弹性安装圆柱体的特性。允许圆柱在流向和横向方向上振动。对于模拟，采用零阻尼系数的质量比值低。主要目的是了解圆柱体背后的涡旋脱落以及唤醒流的过渡特性，从二维（2D）到三维（3D）。雷诺数（RE）从位于层流范围内的150（完全2D流）到1000（完全3D流）变化。降低的速度变化，涵盖了所有三个主要的体内分支（初始分支（IB），上分支（UB）和下部分支（LB））。振荡的圆柱扫除了八轨轨迹。分别为低和高RE值获得了两个分支（IB，LB）和三个分支（IB，UB，LB）振幅响应。圆柱体后面的2-DOF VIV后面的尾流经历了2D到3D流的模式C转变，而不是在文献中仅观察到的仅横向viv的直接模式-B转变。 2DOF VIV缸在降低速度下的2D至3D转变的临界范围约为250，小于1-DOF VIV。同样，此范围随着横向振荡频率比的变化和流向变化而变化。提出了针对2-DOF VIV的地图，突出了用于降低频率和RE组合的不同过渡模式。
The study numerically investigates the three-dimensionality in the flow and two-degree-of-freedom (2 DOF) vortex-induced-vibrations (VIV) characteristics of an elastically mounted circular cylinder. The cylinder is allowed to vibrate in both streamwise and transverse directions. A low value of mass-ratio with the zero damping coefficient is taken for the simulations. The primary aim is to understand the vortex shedding behind the cylinder and the transition characteristics of the wake-flow from two-dimensional (2D) to three-dimensional (3D). The Reynolds number (Re) is varied from 150 (fully 2D flow) to 1000 (fully 3D flow), which lies inside the laminar range. The reduced velocity is varied which covers all three major VIV branches (Initial Branch (IB), Upper Branch (UB), and the Lower Branch (LB)). The oscillating cylinder sweeps the figure-eight trajectory. Two branches (IB, LB) and three branches (IB, UB, LB) amplitude responses are obtained for the low and high Re values, respectively. The wake behind the cylinder with 2-DOF VIV undergoes the mode-C transition of 2D to 3D flow as opposed to the direct mode-B transition observed for transverse only VIV in the literature. The critical Re range of the 2D to 3D transition for the 2-DOF VIV cylinder at a reduced velocity of 6 is around 250, less than the 1-DOF VIV. Also, this range varies with the variation in and the streamwise to transverse oscillation frequency ratio. A map is proposed for the 2-DOF VIV, highlighting the different modes of transition obtained for combinations of reduced frequency and Re.
