质量比对圆柱涡激特性的影响研究

采用有限体积法对不同质量比圆柱在限制流向及不限制流向下的涡激振动进行了研究。圆柱涡激振动系统简化为质量-弹簧-阻尼模型，引入雷诺平均应力模型求解不可压缩粘性Navier-Stokes方程，结合SST  湍流模型对限制流向和不限制流向下圆柱涡激振动进行了数值模拟。研究发现：限制流向和不限制流向时圆柱涡激振动横向振幅均出现了初始激励分支和下端分支, 不限制流向质量比2.0时还出现了超上端分支，其横向振幅最大值为1.05D，是限制流向工况的1.81倍，质量比越大两者相差越小；限制流向和不限制流向两种工况下圆柱涡激振动均发现频率锁定现象，但锁定区间不同；质量比大小对圆柱涡激振动锁定区间也有影响；最后对不同质量比下圆柱涡激振动轨迹进行了讨论分析。

The influence of mass ratio on the vortex induced motion characteristics of circular cylinder

The finite volume method is used to simulate vortex-induced motion of circular cylinder of stream-wise vibration limited and unlimited case considering different mass ratios. The vortex-induced motion system of circular cylinder is simplified into spring-mass-damping model; Reynolds-Averaged Navier-Stokes solver combined with the SST (Shear-Stress Transport) k-ω turbulence model for the Navier-Stokes equation has been used to simulate the vortex induced vibration. The initial branch and lower branch of transverse amplitude has been found both in the stream-wise vibration limited and unlimited case. For the mass ration2.0 cases, the upper branch has emerged for the two degrees of freedom system; the valve of maximum transverse amplitude is 1.05D, which is 1.81 times than that of the single degree of freedom system. The larger the mass ratio is, the smaller the difference is. The Lock-in phenomenon has been discovered both in the stream-wise vibration limited and unlimited case, but the Lock-in range is different. The mass ratios also have influence on lock-in range of the circular cylinder’s vortex-induced vibration. Finally, the trajectory of circular cylinder with different mass ratios is discussed.