摘要
对间距比为1.2和雷诺数为100的串列三圆柱涡激振动进行数值模拟,发现在某个折合流速之后,三圆柱的响应均呈现为随着折合流速增大而增大的弛振现象,平衡位置偏移、低频振动以及旋涡脱落与圆柱运动之间的时机三个因素共同决定了弛振现象的出现.进一步的研究发现,串列三圆柱的弛振现象仅出现在质量比不大于2.0和雷诺数不大于100的工况下.当质量比较大时,串列三圆柱的平衡位置固定不变,且圆柱的振动不规律,使得旋涡脱落与圆柱运动的时机处于变化之中.当雷诺数较高时,最上游圆柱的平衡位置在折合流速较大时回到初始位置,不再参与对圆柱振动的调节,使得圆柱的振动响应不再规律,旋涡脱落与圆柱运动的时机也一直处于变化之中.
Vortex-induced vibrations of three tandem cylinders at the spacing ratio of 1.2 and the Reynolds number of 100 shows that when the reduced velocity is larger than a critical value, the galloping is observed where the amplitudes of three cylinders increase with the reduced velocity. Three factors, including shift of equilibrium position, low vibration frequency and timing between vortex shedding and motion of cylinders, determine the appearance of galloping. Further investigations show that the galloping occurs at a range with lower mass ratio no more than 2.0 and Reynolds number no more than 100. When the mass ratio is large, the equilibrium position is unchanged and the displacements are irregular,which leads to the variation of timing between vortex shedding and motion of cylinders. When Re is large, the shift of the most upstream cylinder is zero and no more accommodate cylinders＇ vibration, which makes the vibration irregular and change of timing between vortex shedding and motion of cylinders.
作者
陈威霖
及春宁
许栋
Chen Weilin;Ji Chunning;Xu Dong(State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300072,Chin)
出处
《力学学报》
EI
CSCD
北大核心
2018年第4期766-775,共10页
Chinese Journal of Theoretical and Applied Mechanics
基金
国家自然科学基金(51579175
51779172)
NSFC-广东联合基金(第二期)超级计算科学应用研究专项资助(U1501501)
国家超级计算广州中心支持项目
关键词
涡激振动
串列三圆柱
弛振
质量比
雷诺数
vortex-induced vibration
three tandem cylinders
galloping
mass ratio
Reynolds number
