Experimental Study of Turbulent Flow Characteristics Around a Circular Bridge Pier

Local scour around bridge piers is a problem of much concern for hydraulic engineers. It’s a complex mechanism caused by the interaction of the flow field around bridge piers on a sediment bed, resulting in foundation instability. Accurate scour depth estimation is aided by a comprehensive understanding of the flow structure effect on the scouring process, which improves the bridge design. The present study has experimentally investigated the three-dimensional flow field around a circular pier model of 5 cm diameter on a plane sediment bed. Under clear-water flow conditions, the instantaneous 3-dimensional velocities (u, v, w) are collected using the Acoustic Doppler Velocimeter (ADV) at different azimuthal planes (θ = 0°, 45°, 90°, 135°, and 180°) from the flow axis. In each azimuthal plane, velocities are obtained on the vertical planes at different elevations (Z = 5 mm intervals) and radial distances (r = 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, 230, and 260 mm) from the pier centroid point. The collected data is analyzed, and the distributions of time-averaged velocities, turbulence intensities, Reynolds shear stresses (RSS), and turbulent kinetic energy (TKE) around the pier in different azimuthal (at θ = 0° and 90°) and vertical planes are presented. This research can help hydraulic engineers better understand the scour mechanism around bridge piers.