基于RANS的圆柱风致涡激振动的CFD数值模拟

CFD numerical simulation of vortex-induced vibration of a circular cylinder based on a RANS method

采用基于RANS方法的SST湍流模型对圆柱涡致振动进行了数值模拟.2D模型建立和网格划分通过专业前处理软件ICEM-CFD实现.保持圆柱的频率不变,通过改变风速来研究圆柱涡致振动的特性.研究结果表明,当约减风速处于4.9—5.1时可以观测到锁定现象,圆柱位移峰值出现在约减风速等于5.023.而且在非锁定区域圆柱的位移反应中可以观察到“拍”的现象.将计算与试验得到的锁定区域进行比较,得到二者结果接近;同时将计算得到的圆柱振动幅值与经验公式和实验数据进行比较,得到了比较满意的结果.

Vortex-induced vibration of a circular cylinder was numerically simulated by using the SST turbulent model that is based on a RANS method. The 2D model foundation and grid partition were achieved in the special pre-processor software ICEM-CFD. The characteristics of vortex induced vibration were researched by changing the velocity of fluid and keeping the frequency of circular cylinder constant. The frequency lock-in phenomenon was observed when the reduced ve-locity is in the range of 4.9-5.1 with a displacement peak at the reduced velocity of 5. 023. In the mean time, a beating behavior was observed in the displacement time-histories of the circular cylinder in the unlock-in region. The regions of lock-in of numerical simulations and experiments are compared, and the results of theirs are approached. The amplitude of the circular cylinder gained by numerical simulation is compared with the results of a semi-empirical formula and experiments, and satisfying results are received.