Comparitive Study of Flow Field Around Circular Uniform Pier in Scour Hole With That Around the Circular Uniform Pier Placed in Rigid Bed

Abstract

In the present study experiments were carried out to measure the flow structure and turbulence characteristics around uniform circular pier in the absence and as well as in the presence of scour hole under clear water condition. The pier comprised of pier diameter = 115 mm. Two experimental runs were conducted in which an Acoustic Doppler Velocimeter (ADV) was used to measure the instantaneous velocity components, turbulent intensity components and Reynolds' stresses at the central line of pier in the upstream plane. A comparative study between these flow structures is therefore presented herein. The flow characteristics around the circular uniform pier in scour hole are moreover same as compared to the flow characteristics around the circular uniform pier without scour hole. The horseshoe vortex can be considered as the basic mechanism causing scour around the bridge piers.