低雷诺数下串列双圆柱涡激振动的数值模拟  

Numerical study of flow-induced vibration of tandem circular cylinders at low Reynolds number

作　　者：张大可[1] 赵西增[1] 胡子俊[1] 王凯鹏[1] 

机构地区：[1]浙江大学海洋学院,浙江舟山316021

出　　处：《哈尔滨工程大学学报》2018年第2期247-253,共7页Journal of Harbin Engineering University

基　　金：国家自然科学基金项目(51479175;51679212);浙江省杰出青年基金项目(LR16E090002)

摘　　要：针对海洋立管中常发生的流致振动问题,本文采用自主研发的CIP-ZJU数值模型,对雷诺数Re=150条件下串列双圆柱的涡激振动进行模拟。该模型在笛卡尔网格系统下建立,采用具有三阶精度的CIP方法求解N-S(navier-stokes)方程,采用浸入边界法处理流-固耦合问题。本文仅考虑圆柱的横向振动,具体分析不同间距比和折合速度,并分别考虑上游圆柱固定和自由振动两种工况,得到柱体振动响应、受力响应和流场信息,验证了本模型在处理柱体涡激振动问题的有效性。结果表明:串列情况下下游圆柱的最大振幅要明显大于单柱的情况,双圆柱涡激振动的阻力系数普遍比单圆柱涡激振动时要小;上游圆柱固定时,下游圆柱的振动频率几乎不由斯特劳哈尔频率控制;而当上游圆柱自由振动时,在折合速度4≤Ur≤5时,上游圆柱后方产生两列涡,使下游圆柱的运动范围限制在两列涡之间,可对其振动产生了抑制作用。In this paper,a finite difference method based on an in-house code,CIP-ZJU,is utilized to simulate two-dimensional flow past tandem circular cylinders at a low Reynolds Number( Re = 150). The model is built on a Cartesian coordinate system,and the Navier-Stokes equation is solved using a CIP method,which has a three-order accuracy. The fluid-structure interactions are treated using an immersed boundary method,and different reduced velocity and spacing ratios are studied. The cylinders can vibrate only in a transverse direction,and the upstream cylinder is considered in two conditions: fixed or with elastically mounted vibration. The force on the cylinders,dynamic response of the cylinders,and the vortex field are analyzed,and results show that the current model can effectively predict VIV. It is found that the maximum vibration amplitudes of the upper cylinder and tandem circular cylinders are much larger than that of a single cylinder,while the drag force of the tandem circular cylinder is generally smaller than that of a single cylinder. When the upper cylinder is fixed,the vibration frequency of the downstream cylinder is not dominated by the Strouhal number,but the situation differs when the upper cylinder moves freely. At a reduced velocity of 4≤Ur≤5,the movement range of the downstream cylinder is limited within two vortexes shed from the upstream cylinder,which restrains vibration of the downstream volume.

关 键 词：串列双圆柱 CIP方法 涡激振动 N-S方程 浸入边界法 数值模拟 雷诺数 涡旋脱落 

分 类 号：O352[理学—流体力学]