准流线型桥梁断面气动力特性的雷诺数效应研究

STUDY ON REYNOLDS NUMBER EFFECT OF AERODYNAMIC CHARACTERISTICS OF QUASI-STREAMLINED BRIDGE SECTION

  • 摘要: 雷诺数效应是桥梁抗风设计研究的关键问题,随着桥梁跨度的增加,桥梁断面雷诺数效应的研究日显重要。选取两个常用的大跨度桥梁准流线型桥梁断面为研究对象,通过风洞试验测得模型表面风压分布,采用压力积分方式获得断面在不同雷诺数下的三分力系数,并分析其变化规律。结果表明:桥梁断面局部细微差异并不能改变三分力系数随雷诺数的变化规律;从模型不同位置处的平均风压系数来看,前缘尖角的下游位置表现出较明显的雷诺数效应,这可能是前缘分离流再附所致;将不同流线型桥梁断面表面风压的无量纲空间分布进行对比,发现不同形状的尖锐棱角仅影响棱角附近平均风压系数极值大小。

     

    Abstract: Reynolds number effect is a key problem in the research of wind-resistance design of bridges. With the increase of bridge span, Reynolds number effect of bridge section becomes more important. Two quasi-streamlined cross-sections of a long-span bridge are selected as the research objects. The wind pressure on model surface is obtained through wind tunnel tests. The aerostatic coefficients of cross-section under different Reynolds numbers are obtained by a pressure integral method. The results show that the relation between aerostatic coefficients and Reynolds numbers is not influenced significantly by section local nuances. In the graph of local averaged wind pressure coefficient, Reynolds number effect is significant at downstream of the leading edge, which may be the result of reattachment of separated flow. The forms of surface wind pressure for different streamlined bridge sections are compared through dimensionless processing. The conclusion is that different sharp edges only affect the extreme value of the average wind pressure coefficient near the edges and corners.

     

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