Active control of vortex-induced vibration of a circular cylinder by using the oscillatory plate immersed in the cylinder wake at low Reynolds number

低雷诺数下尾流场中的振动板对圆柱涡激振动的主动控制研究

As a typical fluid-solid interaction problem,vortex-induced vibration(VIV)is common in engineering,so it is vital to study its control mechanism.Numerical simulations of the active control of VIV of a cylinder are carried out in this study.The splitter plate with harmonic oscillation is used as the control device for the dynamic response of the cylinder.The displacement response,lift and drag coefficient,vibration frequency of the cylinder,energy efficiency of control strategy,and characteristics of the flow field are widely analyzed to reveal the physical mechanism of the control system.The results show that the displacement response of the cylinder can be limited in a small range by the control without feedback in most cases except for high reduced velocity.In addition,the control strategy can be changed through feedback control to keep much superior control effects at the high reduced velocity.The oscillatory splitter plate delays the vortex shedding of shear layers generated on the cylinder,the wake vortices with opposite sense of rotation are paralleled with the streamwise direction,and crosswise distances of them are reduced.Thus,the lift on the cylinder is greatly decreased due to the modification of the flow pattern induced by the oscillatory splitter plate.

涡激振动(VIV)是一种在工程中很常见的典型流固耦合问题,对于其控制机理的研究是至关重要的.本文对圆柱涡激振动的主动控制进行了数值模拟,采用简谐振动的分流板作为圆柱振动响应的控制装置.通过对圆柱的位移响应、升阻系数、振动频率,控制策略的能量效率以及流场的特性进行多方面分析,揭示了控制系统产生效果的物理机制.结果表明,在除高约化速度外的大多数情况下,无反馈控制都能将圆柱的位移响应控制在较小值.而高约化速度时则可以通过反馈控制来改变控制策略,从而也获得较好的控制效果.振动分流板延缓了圆柱上剪切层的脱落,使得旋转方向相反的尾涡平行于流向延伸,减小了其横向距离.因此圆柱的升力由于振动分流板诱导的流型改变而大幅减小.