时间步长对低质量比圆柱涡激振动数值结果的影响

Time-step Effect on VIV Numerical Simulation of a Circular Cylinder at Low Mass-ratio

从圆柱涡激振动数值模拟结果的精度及可信度的角度出发,应用弱耦合算法分析时间步长选取对弹簧支撑低质量比圆柱涡激振动响应结果的影响。计算选取自激振动幅值分支的三个代表性流速,比较不同时间步长下响应结果。比较分析表明:在幅值响应的初始分支和下端分支段,存在最优的时间步长,使得计算效率最高,最接近实验现象;而在幅值响应的上端分支,数值结果要低于实验值,且相位角对求解时间步长非常敏感。

A 2D CFD numerical method based on loose coupling algorithms was adopted to simulate vortex induce vibration of a spring-mounted cylinder at low mass-damping.As the accuracy and reliability were focused,the effect analysis of time-step was applied to three typical reduced velocities.In the initial branch and lower branch,the effective courant number,there exists an optimum time-step which would lead to the highest efficiency and the best match for experiment.And the predicted vibration amplitude at the upper branch is lower than experiment value,while the phase angle is sensitive to time step.