Detached Eddy Simulation Investigation of Turbulence at a Circular Pier with Scour Hole

This paper uses results from detached eddy simulation to reveal the dynamics of large-scale coherent eddies in the flow around a circular pier with an equilibrium scour hole. This is important for the sediment transport because the local scour process is controlled to a large extent by the large-scale coherent structures present in the near-bed region. The present paper investigates the dynamics of these coherent structures, their interactions and their role in entraining sediment in the later stages of the scour process when the horseshoe vortex system is stabilized by the presence of a large scour hole. The pier Reynolds number was 2.06× 105 , outside the range of well-resolved large-eddy simulation (LES). Additionally, scale effects are investigated based on comparison with LES results obtained at a much lower Reynolds number of 16,000 in a previous investigation. The paper provides a detailed study of the dynamics of the main necklace vortices of the horseshoe vortex system, including an investigation...

[1]  W. Rodi.  Comparison of LES and RANS calculations of the flow around bluff bodies , 1997 .

[2]  Kyle D. Squires,et al.  Turbulence modeling applied to flow over a sphere , 2003 .

[3]  P. Moin,et al.  A numerical method for large-eddy simulation in complex geometries , 2004 .

[4]  George Constantinescu,et al.  Assessment of Predictive Capabilities of Detached Eddy Simulation to Simulate Flow and Mass Transport Past Open Cavities , 2007 .

[5]  George Constantinescu,et al.  Nature of flow and turbulence structure around an in‐stream vertical plate in a shallow channel and the implications for sediment erosion , 2009 .

[6]  P. Moin,et al.  Dynamic wall modeling for large-eddy simulation of complex turbulent flows , 2002 .

[7]  G. Constantinescu,et al.  Numerical investigations of flow over a sphere in the subcritical and supercritical regimes , 2004 .

[8]  B. Sumer,et al.  The mechanics of scour in the marine environment , 2002 .

[9]  Sujit K. Bose,et al.  Clear water scour at circular piers : a model , 1995 .

[10]  George Constantinescu,et al.  A numerical investigation of coherent structures and mass exchange processes in channel flow with two lateral submerged groynes , 2007 .

[11]  James R. Forsythe,et al.  Numerical Investigation of Flow Past a Prolate Spheroid , 2002 .

[12]  G. Constantinescu,et al.  Numerical Investigation of Flow Hydrodynamics in a Channel with a Series of Groynes , 2008 .

[13]  George Constantinescu,et al.  A 3D non-hydrostatic model to predict flow and sediment transport in loose-bed channel bends , 2008 .

[14]  Y. Dubief,et al.  On coherent-vortex identification in turbulence , 2000 .

[15]  Willi H. Hager,et al.  Further Results to Time-Dependent Local Scour at Bridge Elements , 2005 .

[16]  Bijan Dargahi,et al.  Controlling Mechanism of Local Scouring , 1990 .

[17]  Kyle D. Squires,et al.  LES and DES Investigations of Turbulent Flow over a Sphere at Re = 10,000 , 2003 .

[18]  George Constantinescu,et al.  Analysis of the flow and mass transfer processes for the incompressible flow past an open cavity with a laminar and a fully turbulent incoming boundary layer , 2006, Journal of Fluid Mechanics.

[19]  F. Sotiropoulos,et al.  On the bimodal dynamics of the turbulent horseshoe vortex system in a wing-body junction , 2007 .

[20]  W. H. Graf,et al.  Flow pattern in the scour hole around a cylinder , 2002 .

[21]  Ming-Hseng Tseng,et al.  Computation of three‐dimensional flow around square and circular piers , 2000 .

[22]  Willi H. Hager,et al.  Down-flow and horseshoe vortex characteristics of sediment embedded bridge piers , 2006 .

[23]  George Constantinescu,et al.  An investigation of the dynamics of coherent structures in a turbulent channel flow with a vertical sidewall obstruction , 2009 .

[24]  T. E. Tokyay,et al.  Validation of a Large-Eddy Simulation Model to Simulate Flow in Pump Intakes of Realistic Geometry , 2006 .

[25]  Marian Muste,et al.  Similitude of Large-Scale Turbulence in Experiments on Local Scour at Cylinders , 2006 .

[26]  B. Sumer,et al.  Numerical and experimental investigation of flow and scour around a circular pile , 2005, Journal of Fluid Mechanics.

[27]  G. Constantinescu,et al.  An investigation of the flow and scour mechanisms around isolated spur dikes in a shallow open channel: 1. Conditions corresponding to the initiation of the erosion and deposition process , 2008 .

[28]  Robert Ettema,et al.  Coherent Structures in the Flow Field around a Circular Cylinder with Scour Hole , 2008 .

[29]  C. Williamson.  Vortex Dynamics in the Cylinder Wake , 1996 .

[30]  Charles Meneveau,et al.  A scale-dependent Lagrangian dynamic model for large eddy simulation of complex turbulent flows , 2005 .

[31]  R. Simpson,et al.  Time-depeiident and time-averaged turbulence structure near the nose of a wing-body junction , 1990, Journal of Fluid Mechanics.

[32]  W. Hager,et al.  Temporal Evolution of Clear-Water Pier and Abutment Scour , 2002 .

[33]  Subhasish Dey,et al.  Characteristics of Horseshoe Vortex in Developing Scour Holes at Piers , 2007 .

[34]  Philippe R. Spalart,et al.  Trends in turbulence treatments , 2000 .