Assessment of High-Velocity Free Surface Flow Interaction with a Bridge Pier in A Curved Channel

Abstract

Free surface flow in the vicinity of bridge piers on a fixed channel bed is a classical problem of open-channel hydraulics. Prior prediction of flow profiles can inform and improve the design of expensive structures, such as high velocity channels and bridges, in particular the height of channel walls and bridge decks. This study used experimental work to simulate free surface flow through a curved rectangular cross section channel containing a single bridge pier. The study investigates the impact of curvature degree of the channel, variations of contraction ratio, discharge (represented by a Froude number), and the length and thickness and shape of the bridge pier on the high velocity free surface flow profile. A simulation of flow in the curved channel with the obstruction was performed for different inflow discharges determining the supercritical flow in the cross-section of a channel constriction. The corresponding afflux (maximum backwater rise in upstream due to bridge constrictions) were measured for each discharge and the measurements yield detailed information about flow structure near the obstruction. The results demonstrated that the values of afflux for the supercritical flow at the curved channel are bigger than those of straight channel, and the difference between the afflux values in both curved and straight channels depends on the curvature degree of the channel.