Coherent Structures in Flat-Bed Abutment Flow: Computational Fluid Dynamics Simulations and Experiments
- 1 March 2003
- journal article
- Published by American Society of Civil Engineers (ASCE) in Journal of Hydraulic Engineering
- Vol. 129 (3), 177-186
- https://doi.org/10.1061/(asce)0733-9429(2003)129:3(177)
Abstract
Numerical computations and laboratory experiments are carried out to investigate the three-dimensional structure of large-scale (coherent) vortices induced by bridge abutments on a flat bed. A finite-volume numerical method is developed for solving the unsteady, three-dimensional Reynolds-averaged Navier–Stokes equations, closed with the turbulence model, in generalized curvilinear coordinates and applied to study the flow in the vicinity of a typical abutment geometry with a fixed, flat bed. The computed flowfields reveal the presence of multiple, large-scale, unsteady vortices both in the upstream, “quiescent,” region of recirculating fluid and the shear-layer emanating from the edge of the foundation. These computational findings motivated the development of a novel experimental technique for visualizing the footprints of large-scale coherent structures at the free surface. The technique relies on digital photography and employs averaging of instantaneous images over finite-size windows to extract coherent eddies from the chaotic turbulent flow. Application of this technique to several abutment configurations yielded results that support the numerical findings.
Keywords
This publication has 21 references indexed in Scilit:
- Numerical Modeling of Helical Static Mixers for Water TreatmentJournal of Environmental Engineering, 2002
- The structure of turbulent flow in a rectangular channel containing a cylindrical rod – Part 2: phase-averaged measurementsExperimental Thermal and Fluid Science, 2000
- Local scour and flow measurements at bridge abutmentsJournal of Hydraulic Research, 1994
- The Oscillation of Horseshoe Vortex SystemsJournal of Fluids Engineering, 1991
- Controlling Mechanism of Local ScouringJournal of Hydraulic Engineering, 1990
- Time-depeiident and time-averaged turbulence structure near the nose of a wing-body junctionJournal of Fluid Mechanics, 1990
- The turbulent flow field around a circular cylinderExperiments in Fluids, 1989
- The turbulent horseshoe vortexJournal of Wind Engineering and Industrial Aerodynamics, 1980
- Theoretical Approach To Prediction Of Local Scour Around Bridge PiersJournal of Hydraulic Research, 1980
- The laminar horseshoe vortexJournal of Fluid Mechanics, 1979