Numerical Modeling of Three-Dimensional Flow Field Around Circular Piers

TLDR

A three‑dimensional FLUENT model was employed to simulate separated turbulent flow around vertical circular piers in clear water, using multiple turbulence models and validating the results against experimental data. The study shows that several k‑ε turbulence model variants can satisfactorily reproduce measured velocity profiles around circular piers, though they underestimate bed shear stress, whereas the Reynolds stress model accurately captures both velocity and shear stress distributions, demonstrating that a robust 3‑D hydrodynamic model can effectively supplement experiments to elucidate flow fields and scour initiation around piers of various sizes.

Abstract

A three-dimensional numerical model FLUENT is used to simulate the separated turbulent flow around vertical circular piers in clear water. Computations are performed using different turbulence models and results are compared with several sets of experimental data available in the literature. Despite commonly perceived weakness of the k-ε model in resolving three-dimensional (3D) open channel and geophysical flows, several variants of this turbulence model are found to have performed satisfactorily in reproducing the measured velocity profiles. However, model results obtained using the k-ε models show some discrepancy with the measured bed shear stress. The Reynolds stress model performed quite well in simulating velocity distribution on flat bed and scour hole as well as shear stress distribution on flat bed around circular piers. The study demonstrates that a robust 3D hydrodynamic model can effectively supplement experimental studies in understanding the complex flow field and the scour initiation process around piers of various size, shape, and dimension.