The Local Flow around the Upstream Side of Bridge Piers

Abstract

The local flow around bridge piers has such a complicated mechanism due to fluctuations and three-dimensionality that the result of analytical study has not explained clearly the horseshoe vortex and down flow which characterize this local flow and play an important role on local scour. In this paper the author attempts first to make clear the fundamental characteristics of the local flow by experiments. For that purpose detailed measurements are made under laminar conditions as well as under turbulent conditions on the flow around a pier settled on the flat bed of a channel. He attempts secondly to propose a flow model on the basis of the experimental results in order to analyse the three-dimensional characteristics of local flows. Lastly, the results of the analysis are shown to be in fairly good agreement with the measured value.