Experimental study of turbulent flow characteristics around a circular compound bridge pier

The cylindrical piers built on large foundations or caissons are compound or non-uniform piers and are often adopted as bridge substructure design on the Indian rivers. The present study has experimentally investigated the flow field and scour around a compound pier consisting of a circular pier of diameter (D = 0.05 m) resting over a circular foundation of diaeter (D* = 2D) 0.10 m with the footing top surface positioned at the bed level. Under clearwater flow conditions, the flow and turbulence characteristics around a circular compound pier with an equilibrium scour hole are experimentally measured to evaluate the foundation geometry effect on the scouring process. The instantaneous velocities (u, v, w) are measured using an Acoustic Doppler Velocimeter (ADV) at distinct azimuthal planes. The data is analyzed and graphically presented as time-averaged velocities, turbulence intensities, and turbulent kinetic energy. This research will benefit hydraulic engineers better comprehend the foundation geometry effects on the scouring process at compound bridge piers.