分体式双箱梁涡振气动控制措施数值模拟

Numerical Simulation of Pneumatic Control Measures for Split Double Box Girder Vortex Vibration

分体式钢箱梁可较大幅度提高颤振临界风速,但较容易引起桥梁涡振,以国内某大跨悬索桥涡激共振为背景,对分体式双箱梁分别增设风障、导流板和纵向格栅后的涡振响应进行纯数值模拟,对比分析了导流板和纵向格栅在一阶正对称竖弯、一阶反对称扭转和七阶竖弯模态,风攻角范围为+3°^-3°情况下的涡振控制效果,基于上述气动措施的流场特性,对其涡振减振机理进行了研究。研究结果表明,风障可以有效降低竖弯涡振振幅,但对扭转涡振振幅具有放大作用;导流板的涡振控制效果与风攻角和风速有关;纵向格栅对正、负风攻角下的竖弯和扭转涡振均有很好的控制效果。

Split-type steel box girder can greatly increase the critical wind speed of flutter,but it is easy to cause bridge vortex vibration.Based on the vortex-induced resonance of a large-span suspension bridge in China,wind shields and deflectors are added to the split double box girder,respectively.The vortex response of the longitudinal grid is simulated by numerical simulation.The first-order positive symmetrical vertical bending,first-order antisymmetric torsion and seventh-order vertical bending mode are compared between the deflector and the longitudinal grid with the wind angle of attack range from-3° to+3°.The vortex vibration control effect is studied based on the flow field characteristics of the above aerodynamic measures.The results show that the wind barrier can effectively reduce the vertical vortex vibration amplitude,but it has an amplifying effect on the torsional vortex amplitude;the vortex vibration control effect of the deflector is related to the wind angle of attack and wind speed.The longitudinal grid has a good control effect on the vertical bending and torsional vortex vibration under positive and negative wind angles of attack.