阻尼比对串列双圆柱二自由度涡激振动及传热影响的数值研究

Numerical Study on the Effect of Damping Ratio on Vortex-Induced Vibration and Heat Transfer of Two Degrees of Freedom Double Cylinders in Series

摘要: 采用数值方法研究了流体流过刚性串列双圆柱产生涡激振动(VIV)时的流动和传热。研究对象是二维的，雷诺数Re = 150，双圆柱的间距比为8，且都具有二平动自由度(2DOF)。采用有限体积法求解Navier-Stokes方程获得流场，同时用四阶龙格–库塔算法耦合求解圆柱的运动。主要研究了在不同折合速度Ur下，不同阻尼比(ζ = 0, 0.01, 0.1)时对上下游二自由度(2DOF)圆柱涡激振动时传热的影响。数值计算结果表明：当2 < Ur ≤ 6时，随着折合速度Ur的增大，在不同阻尼比时，上游圆柱的时间平均努塞尔数均先增大后减小。当Ur = 5时，阻尼比从ζ = 0增大为ζ = 0.1时，下游圆柱的时间平均努塞尔数减小8.74%。当折合速度Ur > 5后，下游圆柱的运动轨迹受上游圆柱尾迹区形成的波动的影响，下游圆柱的运动轨迹呈现不规则变化。

Abstract: The flow and heat transfer of vortex-induced vibration (VIV) generated by fluid flowing through a rigid tandem double cylinder are studied numerically. The Reynolds number is 150 and the clear-ance ratio of the two cylinders is 8, and both of them have two degree of freedom (2DOF). The finite volume method is used to solve Navier-Stokes equations to obtain the flow field, and the fourth order Runge-Kutta algorithm is used to solve the cylinder motion. The influence of different damping ratios (ζ = 0, 0.01, 0.1) on the heat transfer of a 2DOF cylinder under vortex-induced vibration at different reduced velocities Ur is studied. The numerical results show that when 2 < Ur ≤ 6, with the increase of reduced velocity Ur, the time mean Nusselt number of upstream cylinder increases first and then decreases with different damping ratios. When Ur = 5, the damping ratio increases from ζ = 0 to ζ = 0.1, and the time mean Nusselt number of downstream cylinder decreases by 8.74%. When the reduced velocity Ur > 5, the motion trajectory of the downstream cylinder is affected by the fluctuation of the wake region of the upstream cylinder, and the motion trajectory of the down-stream cylinder shows irregular changes.