Title: Numerical investigations of the round-nosed bridge pier length effects on the bed shear stress
Authors: Bouabdellah Guemou; Abdelali Seddini; Abderrahmane Nekkache Ghenim
Addresses: Ctr Univ Ain Temouchent, BP 284 Ain Temouchent, Algeria ' Department of Hydraulics, University of Tlemcen, Algeria ' Department of Hydraulics, University of Tlemcen, Algeria
Abstract: Local scour around bridge piers is a complex phenomenon that threatens the river bridges safety. In this paper, we have studied the influence of the aerodynamic shape of the bridge pier on the bed shear stress, and we have carried out a parametric study considering the length of the aerodynamic shape that better reduces the bed shear stress. For that purpose, a number of simulations have been carried out using a finite volume method (FVM) and for the turbulence model, we have chosen the detached eddy simulation (DES) for it's capability to capture the rich dynamics of the horseshoe vortex at the upstream junction between the pier and the bed. The present parametric study shows that the aerodynamic shape of the bridge pier strongly affects the flow pattern around it; also, the result reveals that, with a constant width, the length of the best round nosed pier shape must not exceed 2.5 the width. Beyond that, the bridge pier length does not have any effects on the bed shear stress.
Keywords: bridge piers; local scour; aerodynamic shape; simulation; round-nosed piers; pier length; bed shear stress; river bridges; bridge safety; finite volume method; FVM; turbulence modelling; detached eddy simulation; dynamic modelling horseshoe vortex; flow patterns.
Progress in Computational Fluid Dynamics, An International Journal, 2016 Vol.16 No.5, pp.313 - 321
Received: 18 Mar 2014
Accepted: 30 Mar 2015
Published online: 08 Aug 2016 *