【摘要】 利用计算流体力学(CFD)方法,研究了低雷诺数下圆柱顺流向与横流向耦合涡激振动特性。利用Fluent求解器求解二维不可压缩粘性非定常Navier-Stokes方程,并嵌套用户自定义函数(UDF)求解圆柱运动控制方程,结合动网格技术实现双向流固耦合,对圆柱进行了单自由度和两自由度涡激振动的数值模拟,获得了雷诺数Re=150下的圆柱涡激振动幅值比、频率比、升力系数、阻力系数以及升力与横向位移间的相位角随约化速度的变化规律,捕捉到涡激振动的"锁定"、"相位开关"以及"拍"等现象,锁定区域对应约化速度范围为4.5～8.0。对比单自由度及两自由度模拟结果,发现考虑顺流向的振动会使横流向振幅有所增加。更多还原

【Abstract】 With Computational Fluid Dynamics method, the characteristics of vortex-induced vibration for a circular cylinder in flow direction and transverse under low Reynolds number are studied. Navier-Stokes equations are solved by using FLUENT solver and the motion control equations of the cylinder are solved by using User-Defined Function. With the dynamic mesh technique of FLUENT, the two-way fluid-structure interaction is realized. The numerical simulation of single degree-of-freedom and two degree-of-freedom vortex-induced vibration of the cylinder are simulated. Thus, the amplitude ratio, frequency ratio, lift coefficient and resistance of the cylinder vortex-induced vibration at Re=150 are obtained. The "lock-in",“beat vibration”and "phase switch" phenomenon of vortex-induced vibration are caught. The results show that the corresponding lock-in region is for U_r=4.5～8.0. Compared with the simulation results of single DOF and two-DOF, it shows that the vibration along the flow direction has a gain effect on the vibration in the cross flow direction.更多还原