桥梁断面中间开槽对颤振稳定性的影响

Influence of Central Slot on Bridge Box Girder's Flutter Instability

用计算流体动力学 (CFD)方法研究了箱型桥梁断面中间开槽前后颤振临界风速的变化 ,结果表明中间开槽的效果与断面头部形状和开槽宽度有密切关系 .当头部形状或开槽宽度不合适时 ,中间开槽不但不能提高颤振临界风速 ,反而降低了断面的颤振稳定性 .这种计算分析结果也和实验结果相符合 .并进一步从不同断面周围流场的特征方面对这种现象做出解释 。

Using computational fluid dynamics (CFD) method we studied the critical flutter wind speed of bridge box girder with or without central slot.The results show that the shape of section head and width of slot have large impact on the effect of slot.When the head's shape or width of central slot is unsuitable,central slot decreases critical flutter wind speed instead of increasing it.These computational results are agree well with experiments.Further explanation is given based on the characters of flow pattern around different sections.The effect of slot is mainly determined by the shear layer initiated from upstream box's edge and the flow through the slot.When the shear layer is collided with the downstream box or the flow through the slot having the same direction with motion of girder section,the central slot decreases the critical flutter wind speed.