圆端形桥墩侧向紊流宽度的试验研究

Experimental study of lateral turbulent flow width at round-ended pier

在水槽中进行概化试验,采用三维声学多普勒测速仪(ADV)测量圆端形桥墩周围三维流场及紊动强度分布.分析有桥墩时的紊流强度垂向分布及有、无桥墩时紊流强度比值的横向分布变化,分析结果表明,垂线上紊流强度最大位置在0~0.2h与0.8h^1.0h两个区间,桥墩对紊流强度的变化影响存在极值,极值大小和出现位置与流速有关,流速越大,极值越大,且极值位置与桥墩的距离也越大.根据极值出现位置离桥墩距离确定紊流宽度,给出了桥墩紊流宽度与弗汝德数的关系.

The conceptual experiment has been done in a flume, and the three-dimensional ultrasonic Doppler speedometer ADV is used to measure the 3-D flow field and the turbulence intensity field around a round-ended pier. The vertical distribution of the turbulence intensity with the pier and the traverse distribution of the turbulence intensity ratio in the flume with or without the pier have been analyzed. The results show that the location of the maximum of the turbulence intensity on the perpendicular line is to present an inhomogeneous distribution from 0 to 0.2 h and from 0. 8 h to 1 h ; the influence of the pier on the turbulence intensity can come to a maximum ; and the value of the maximum and the distance from the location where the maximum occurs to the pier both increase along with the increase of the flow velocity. Based on the distance, the relationships between the width of the turbulence with the pier and the Froude number have been presented.