Coherent structures in flat-bed abutment flow: Computational fluid dynamics simulations and experiments

Antonis Chrisohoides, Fotis Sotiropoulos, Terry W. Sturm

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Numerical computations and laboratory experiments are carried out to investigate the three-dimensional structure of largescale (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-Stockes equations, closed with the k-ω turbulence model, in generalized curvi-linear 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.

Original languageEnglish (US)
Pages (from-to)177-186
Number of pages10
JournalJournal of Hydraulic Engineering
Volume129
Issue number3
DOIs
StatePublished - Mar 2003

Keywords

  • Bridge abutments
  • Models
  • River beds
  • Scour
  • Turbulence

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