TY - JOUR
T1 - Coherent structures in flat-bed abutment flow
T2 - Computational fluid dynamics simulations and experiments
AU - Chrisohoides, Antonis
AU - Sotiropoulos, Fotis
AU - Sturm, Terry W.
PY - 2003/3
Y1 - 2003/3
N2 - 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.
AB - 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.
KW - Bridge abutments
KW - Models
KW - River beds
KW - Scour
KW - Turbulence
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U2 - 10.1061/(ASCE)0733-9429(2003)129:3(177)
DO - 10.1061/(ASCE)0733-9429(2003)129:3(177)
M3 - Article
AN - SCOPUS:0037339532
SN - 0733-9429
VL - 129
SP - 177
EP - 186
JO - Journal of Hydraulic Engineering
JF - Journal of Hydraulic Engineering
IS - 3
ER -