Flow-Induced Vibration of a Cantilevered Cylinder in the Wake of a Fixed Cylinder
作者单位：Center of Turbulence Control Harbin Institute of Technology (Shenzhen)
会议名称：《第十二届全国流体力学学术会议》
会议日期：2022年
学科分类：080704[工学-流体机械及工程] 080103[工学-流体力学] 08[工学] 0807[工学-动力工程及工程热物理] 0801[工学-力学（可授工学、理学学位）]
关 键 词：flow-induced vibration cantilever cylinder gap shear layer galloping
摘 要：This work presents an experimental study of the flow-induced vibration of a cantilevered circular cylinder in the wake of another fixed cylinder for the diameter ratio d/D = 0.24 – 1.0 and spacing ratio L/d = 1.0 – 5.5 under the reduced velocity U = 3.8 – 68.3, where d and D are diameters of the upstream and downstream cylinders, respectively, and L is the spacing from the upstream cylinder center to the front stagnation point of the downstream cylinder. Measurements are done for the vibration response, vortex shedding frequency, surface pressure distribution, and flow structures via laser vibrometer, hotwire anemometer, pressure scanner, and particle-image-velocimetry(PIV) system, respectively. A smaller d/D and/or L/d is more prone to causing galloping generation and hysteresis in the galloping response. The galloping vibration involves alternate reattachment and switch of the gap shear layers. The switch of the gap shear layers leads to reduced added mass and added damping, hence exciting and sustaining the vibrations. The initiation of galloping generation wades through pre-initial, initial, and late transitions before reaching steady vibration, where the work done by fluid flow is larger than the dissipation. In addition, this study presents(ⅰ) the roles of effective added mass and effective added damping in vibration initiation and sustainability,(ⅱ) wake structure evolutions in the streamwise and spanwise directions, and(ⅲ) detailed fluid-structure interactions involved.