不同迎流攻角下正三角柱流致振动数值模拟研究  

Numerical simulation for flow-induced vibration of regular triangular column under different angles of attack

作　　者：卫昱含 及春宁[1] 许栋[1] 陈威霖[1] WEI Yuhan;JI Chunning;XU Dong;CHEN Weilin(State Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300072

出　　处：《振动与冲击》2022年第3期278-286,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金(51779172,51579175)。

摘　　要：采用嵌入式迭代浸入边界法对不同迎流攻角下正三角柱的流致振动(VIV)进行了二维数值模拟研究,其中迎流攻角为α=0°~60°(当α=60°时三角柱顶点迎流),雷诺数为Re=100,质量比为m*=5和折合流速为U r=2~20。详细分析了不同迎流攻角下横流向振幅、振动频率、水动力系数、升力与位移的相位差以及尾涡模式随折合流速变化的情况。结果发现,三角柱振动随迎流攻角表现为3种不同的振动模式:涡振-驰振联合模式(α=0°~15°)、涡振-驰振分离模式(α=20.0°~22.5°)和涡振模式(α=25°~60°)。选取α=0°、α=20°、α=60°3个迎流攻角详细论述了不同模式下三角柱的振动特性。此外,还发现虽然三角柱在迎流攻角α=0°时关于来流方向对称,三角柱的平衡位置在某些折合流速下出现了偏移,该现象与升力中偶次谐波分量的出现有关。最后,应用准稳态分析得到了驰振出现的攻角范围,结果与数值模拟的情况吻合较好,说明准稳态分析可以准确预测三角柱驰振的攻角范围。Here,the 2D numerical simulation for flow-induced vibration of a regular triangular column under different angles of attack was studied by using the embedded iterative immersed boundary method.The angle of attack range wasα=0°-60°(a vertex of regular triangular column faces flow whenα=60°),Reynolds number was Re=100,the mass ratio was m*=5,and the reduced velocity was U r=2-20.The variation of cross flow amplitude,vibration frequency,hydrodynamic coefficient,phase difference between lift and displacement and wake vortex mode with change of reduced velocity under different angles of attack were analyzed in detail.The results showed that the triangular column vibration has 3 different vibration modes of the combined vortex-induced vibration(VIV)and galloping mode atα=0°-15°,the separated VIV and galloping mode atα=20.0°-22.5°,and the VIV mode atα=25°-60°;vibration characteristics of the triangular column under 3 modes are described in detail at three attack anglesα=0°,20°and 60°,respectively;although the triangular column is symmetric about incoming flow direction whenα=0°,its balanced position is offset at some reduced velocities,this phenomenon is related to occurrence of even harmonic components in lift;the attack angle range of galloping is obtained by using the quasi-steady state analysis,this range agrees better with that of numerical simulation,so the quasi steady state analysis can accurately predict the attack angle range of triangular column galloping.

关 键 词：流致振动 正三角柱 平衡位置 准稳态分析 

分 类 号：P751[交通运输工程—港口、海岸及近海工程] TB531[天文地球—海洋科学]