基于双向流固耦合的灯柱涡激振动分析

Numerical simulation of the vortex-induced vibration of a lamppost based on the bidirectional fluid-solid interaction

对有焊缝圆形断面的灯柱在不同风向角下的涡激振动响应进行了数值模拟研究。基于计算流体动力学方法,采用大涡模拟湍流模型,求解不可压缩流体N-S方程。通过编写自定义程序代码UDF,对Fluent软件进行了二次开发,将求解结构振动响应的Newmark-β算法嵌入到Fluent软件中。结合"刚性边界层运动区域+动网格运动区域"的动网格划分策略,对灯柱结构涡激振动响应进行了双向流固耦合数值模拟。研究结果表明:当来流风速处于5.25m/s(0°风向角工况)和6.25m/s(90°和-90°风向角工况)附近时,会出现"锁定"现象;而在其他风速区间,会出现"拍"现象。该流固耦合计算方法捕捉到了灯柱从"拍"到"锁定"再回到"拍"现象的全过程。在锁定区域附近,灯柱的涡激共振位移幅值远大于在非锁定区域灯柱的涡激共振位移幅值。

Numerical simulation of the vortex-induced vibration response of a lamppost with a circular section of weld at different wind direction angles is carried out. Based on the computational fluid dynamics method, the large eddy simulation turbulence model is used to solve the incompressible fluid N-S equation. Fluent software is redeveloped by writing a custom program code UDF program, and the Newmark-β algorithm for solving the structural vibration response is embedded into Fluent. The dynamic meshing strategy of "rigid boundary layer motion region with moving mesh motion region" is used to simulate the vortex-induced vibration response of the lamp column structure by two-way fluid-solid coupling. The results show that when the incoming wind speed is near 5.25 m/s (0° wind direction) and 6.25 m/s (90° and -90° wind direction), the phenomenon of "lock-in" occurs, while the phenomenon of "shooting" appears in the wind speed interval. The fluid-solid coupling calculation method proposed successfully capturs the whole process of the lamppost from "shooting" to "locking" and then returning to "shooting" phenomenon. Vortex-induced resonance displacement value of the lamppost near the locked area is much larger than the displacement value of the non-lock-in area.