A Large Eddy Simulation study of the bed shear stress distributions around isolated and multiple groynes

2008-12-01
Constantinescu, G.
Köken, Mete
McCoy, A.
Large Eddy Simulation is used to investigate the main coherent structures playing a role in the erosion process (e.g., horseshoe vortex system forming around the base of the groynes, eddies shed in the separated shear layer) and the associated bed shear stress distributions around isolated and multiple groynes placed in straight channels. For isolated groynes we investigate the flow at conditions corresponding to the start of the scouring process (flat bed) and to its end (equilibrium scour bathymetry). Also, we consider the flow past two vertical groynes and we study the effect of groyne submergence (fully emerged vs. 40% relative submergence depth) on the horseshoe vortex system forming at the base of the upstream groyne and bed shear stress distribution in the groynes region. Large amplifications of the turbulence (e.g., resolved kinetic energy) inside the horseshoe vortex system and of the bed shear stress below are observed in all the cases. © 2008 Taylor & Francis Group, London.
5th IAHR-Symposium on River, Coastal and Estuarine Morphodynamics, RCEM 2007

Suggestions

A DES Study for the Role of Contraction Ratio on the Coherent Structures Caused by Two Spill Through Abutments
Köken, Mete (2013-09-13)
Detached Eddy Simulation (DES) is used to investigate the changes in the horseshoe vortex system and the bed shear stress distribution forming around the base of spill-through bridge abutments located at two sides of the channel for two different contraction ratios. DES is conducted at a channel Reynolds number of 45,000, and the incoming flow was fully turbulent that contains resolved turbulence fluctuations. Simulations are conducted at flat bed conditions representing the initiation of the scour process....
An investigation of the flow and scour mechanisms around isolated spur dikes in a shallow open channel: 2. Conditions corresponding to the final stages of the erosion and deposition process
Köken, Mete (American Geophysical Union (AGU), 2008-08-05)
Large eddy simulation (LES) is used to investigate the flow around a vertical spur dike in a straight channel with equilibrium scour bathymetry and the scour mechanisms in the later stages of the erosion deposition process. The equilibrium bathymetry is obtained from an experiment conducted at the same relatively low channel Reynolds number (Re = 18,000). Flow visualizations are used to complement the information obtained from the numerical simulation. The present investigation demonstrates that large-scale...
An investigation of coherent structures in the wake of a bridge abutment at equilibrium bed scour conditions
Köken, Mete (2007-01-01)
The database from a Large Eddy Simulation (LES) calculation is used to investigate the dominant coherent structures in the wake of a vertical bridge abutment in a straight channel with deformed bed corresponding to equilibrium scour bathymetry. The bathymetry is obtained from an experiment conducted at the same Reynolds number. The incoming flow is fully turbulent in both experiment and simulation. Dye visualizations are used to validate the numerical predictions. It is observed the directions at which the ...
A numerical study on the dynamic behaviour of gravity and cantilever retaining walls with granular backfill
Yıldız, Ersan; Özkan, M. Yener; Department of Civil Engineering (2007)
Dynamic behaviour of gravity and cantilever retaining walls is investigated by finite element method, incorporating the nonlinear elasto-plastic material properties of soil and seperation of the wall and backfill. Two dimensional finite element models are developed employing the finite element software ANSYS. The wall is modelled to rest on a soil layer allowing translational and rotational movements of the wall. Soil-wall systems are subjected to harmonic and real earthquake motions with different magnitud...
A laboratory study of anisotropy in engineering properties of Ankara clay
İspir, Mustafa Erdem; Ergun, Mehmet Ufuk; Department of Civil Engineering (2011)
Anisotropy in engineering properties of soils occurs due to the depositional process forming the soil fabric and/or different directional stresses in soil history. This study investigates the anisotropy in undrained shear strength and drained compressibility of preconsolidated, stiff and fissured Ankara Clay. The compressibility behavior is determined using standard oedometer testing while the shear strength anisotropy is investigated through large diameter unconsolidated-undrained triaxial testing on undis...
Citation Formats
G. Constantinescu, M. Köken, and A. McCoy, “A Large Eddy Simulation study of the bed shear stress distributions around isolated and multiple groynes,” Enschede, Hollanda, 2008, vol. 2, Accessed: 00, 2021. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84858114699&origin=inward.