低雷诺数下直圆柱和波型圆柱受迫振动的数值研究

Numerical simulation for forced oscillations of right cylinders and wavy cylinders under low Reynolds number

对低雷诺数下(Re=150)的直圆柱和波型圆柱在均匀来流中横向受迫振动问题进行了数值模拟研究。通过改变运动圆柱的振动频率和振幅,对比分析直圆柱和波型圆柱所受的升阻力,确定各自的锁定区间并分析在锁定状态下升力及尾涡的变化特性。数值结果表明:虽然波型圆柱在静止情况下能够完全抑制卡门涡街,但在受迫振动下其升阻力随振动频率的变化趋势与直圆柱相似;波型圆柱对升力和阻力的抑制分别体现在低频和高频段;升力曲线在锁定和非锁定状态下表现不同;锁定状态下,直圆柱尾流区的泻涡模式由振动频率控制,观察到2S和C(2S)两种模式;波型圆柱尾流区观察到唯一一种泻涡模式。

Both right cylinders and wavy ones’forced oscillations normal to incoming uniform flow under low Reynolds number(Re=150)were numerically investigated.The effects of oscillation amplitude and frequency on hydrodynamic forces exerted on these cylinders were examined.Their lock-in regions were determined and under lock-in states varying characteristics of lift force and wake were analyzed.The numerical simulation showed that although wavy cylinders can fully suppress Karman vortex street in static cases,the variation trend of their hydrodynamic forces with their oscillation frequency is similar to that of right cylinders under forced oscillation;wavy cylinders’suppressing lift and drag forces appear within lower and higher frequency regions,respectively;lift force curves have different performances under a lock-in state and a non-lock-in state;under a lock-in state,vortex modes in wake regions of right cylinders are controlled by oscillation frequency,2S and C(2S)modes are observed,while only one vortex mode is observed in wake regions of wavy cylinders.