CSCE 2013 General Conference - Congrès général 2013 de la SCGC
Montréal, Québec
May 29 to June 1, 2013 / 29 mai au 1 juin 2013
GEN-022
CFD Modelling of 3-D Turbulent Flow around a Circular Bridge Pier
M.N. Sakib, S.S. Li and A.M. Zsaki
Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, Quebec
Abstract: The flow field around a pier is complex in detail and the complexity is further increased with the
development of a scour hole. As flow-induced scouring around piers can cause bridge failures, a good
understanding of the flow field is important to the safe design of hydraulic structures. The objective of this
paper is to simulate the free surface flow around a pier in a fixed scour hole, and to further determine
shear stress distributions. The simulations are based on the Reynolds averaged momentum and
continuity equations in three dimensions, with the k-ɷ model for turbulence closure. Regions around the
pier and near the bottom are resolved with sufficiently fine meshes so as to capture detailed velocity
structures. Simulations were carried out under the same geometric and hydraulic conditions as available
laboratory experiments. The simulated flow velocities and bed shear stresses are shown to compare well
with the experimental data. The model results exhibit realistic vortex features around the pier and in the
wake region behind. Velocity profiles were extracted from the model results at selected locations in the
approach flow region, in the scour hole and downstream of the scour. They are useful for the assessment
of the suitability of various methods for estimates of the bed shear stress. The implications to sediment
transport and scouring are discussed in the paper.
Keywords: circular pier, scour hole, turbulence, flow simulation, vortex features.