异形孔桥墩附近河道水流流动特性

Flow characteristics around bridge pier with special orifice

采用三维水动力数学模型,计算分析了异形孔桥墩附近河道的水流流动特征,比较了建桥前后桥址附近河道的流场分布,得到了异形孔桥墩附近河道的水流流场、墩前阻水范围,桥墩下游的尾流区长度、宽度以及河床附近的涡量、切应力等的分布规律,并给出了墩前阻水长度,尾流区长度和宽度以及河床表面最大切应力与墩前断面弗劳德数的关系及经验公式.结果表明,异形孔桥墩对桥址附近的水流流动影响显著,墩前阻水长度与墩前断面弗劳德数呈正相关关系,而尾流区长度和宽度以及河床表面最大切应力与墩前断面弗劳德数呈线性关系.

The flow characteristics around the bridge pier with a special orifice were simulated and analyzed using the 3-D hydrodynamic mathematical model.The velocity fields near the bridge site were compared before and after the bridge construction.The velocity field around the bridge pier with a special orifice,the hindrance length for flow approaching bridge pier,the length and width of the wake region downstream of the bridge pier,the vorticity and shear stress distribution near river bed were obtained.The relationships of the hindrance length for flow approaching bridge pier,the length and width of the wake region downstream of the bridge pie,and the maximum bed shear stress with the Froude number upstream of the bridge pier were provided,and their experiential formulae were also obtained.The results show that the bridge pier with a special orifice has a remarkable influence on water flow near the bridge pier,the hindrance length for flow approaching bridge pier has a positive correlation with the Froude number upstream of the bridge pier,and the length and width of the wake region and the maximum bed shear stress vary approximately linearly with the Froude number upstream of the bridge pier.