This study investigated flow characteristics around a cylindrical pier under a partially submerged bridge deck. The tests were carried out in clear water conditions for both free-surface and pressure-flow conditions. Three-dimensional velocity measurements were taken at different positions along the centreline of the flume using an acoustic Doppler velocimeter. The results showed that the longitudinal and vertical velocity components of the pressure-flow increased in the vicinity of the pier as compared with those of the free-surface flow. Large values of the turbulence intensities, turbulent kinetic energy and Reynolds shear stress were observed at the upstream edge of the bridge deck within the shear layer and downstream of the pier under the deck due to the generation of wake vortices. Flow contraction and acceleration around the pier's sides resulted in a local increase of the bed shear stress.

中文翻译：

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部分淹没桥面下圆柱墩周围流动特性

本研究调查了部分淹没桥面下圆柱形桥墩周围的流动特性。对于自由表面和压力流动条件，测试都是在清水条件下进行的。使用声学多普勒测速仪在沿水槽中心线的不同位置进行三维速度测量。结果表明，与自由表面流相比，在墩附近压力流的纵向和垂直速度分量增加。由于尾流涡的产生，在剪切层内的桥面板上游边缘和桥面板下桥墩下游观察到湍流强度、湍流动能和雷诺剪切应力的较大值。码头周围的水流收缩和加速'