A review on hydrodynamics of horseshoe vortex at a vertical cylinder mounted on a flat bed and its implication to scour at a cylinder

Gazi, Ainal Hoque; Afzal, Mohammad Saud

doi:10.1007/s11600-020-00439-8

Cited by 26 publications

(10 citation statements)

References 94 publications

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“…One was that there was no bow wave that can reduce the upstream vortex in submerged pile conditions [17]. The other was that the velocity and strength of vortex varied not largely when Re D > 10 4 [12]. Therefore, scour depth at K C was thought to increase little when h/h c ≥ 5 in the submerged tests.…”

Section: Temporal and Equilibrium Scour Depthsmentioning

confidence: 98%

“…With the increasing submergence ratio, d Ce /D increased linearly when h/h c ≤ 4.0. These characters were the result of the increased relative boundary layer thickness (δ/D) and Re D that related to the strength of the horseshoe vortex upstream of the pile [9,12].…”

Section: Temporal and Equilibrium Scour Depthsmentioning

confidence: 99%

“…Specifically, they found that in accordance with the current conditions alone, the horseshoe vortex underwent substantial changes in waves depending on the Keulegan-Carpenter number. Afzal et al [11], Gazi and Afzal [12] and Gautam et al [13] applied the Level-Set method to a three-dimensional computational fluid dynamics model to study the formation process of vortices around the pier in waves, currents or combined waves and currents. While Liang et al [3], Yang et al [4], Yao et al [7] and Roulund et al [9], obtained the equilibrium scour depth by adapting the temporal scour depth data to curves, Cheng et al [14], Gazi and Afzal [15] and Gazi et al [16] derived the equilibrium scour depth equations on the concept of the volume of sediment transport and flow turbulence energy through mathematical analysis methods.…”

Section: Introductionmentioning

confidence: 99%

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Scour at a Submerged Square Pile in Various Flow Depths under Steady Flow

Wu²,

Liang³

et al. 2022

Water

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Local scour around submerged piles in currents are common in coastal and offshore engineering. This paper studies the influences of the submergence ratio (flow depth to pile height) on local scour around a square pile in steady flow. Submergence ratio ranging from 1–4, as well as two unsubmerged tests, were tested with a 10 × 10 square pile of 20 cm height. The three-dimensional profiles were measured to study the scour and deposition characteristics. Results show that the maximum scour depth was always at the upstream corner points rather than at the symmetry center point of the pile. The temporal maximum scour depth achieved its equilibrium sate in less than 4 h for each test. The equilibrium scour depths at the upstream corner points were independent of the submergence ratio when the latter was larger than 1.5. These findings give meaningful reference to the numerical simulations and local scour depth protections in the submerged pile cases deeper than which the flow depth does not affect the equilibrium scour depth.

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Section: Temporal and Equilibrium Scour Depthsmentioning

confidence: 98%

Section: Temporal and Equilibrium Scour Depthsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Scour at a Submerged Square Pile in Various Flow Depths under Steady Flow

Wu²,

Liang³

et al. 2022

Water

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“…Horseshoe vortices are mainly generated by down-flow and separation of the flow upstream of the pier. The turbulence intensity and the increased bed shear stress within the HV system carry the sediment particles and develop the local scour around the pier (Gazi and Afzal, 2020).…”

Section: Introductionmentioning

confidence: 99%

Large eddy simulation of flow around semi-conical piers vertically mounted on the bed

Aghaee-Shalmani

Hakimzadeh

2022

Environ Fluid Mech

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In this paper, details, and results of three-dimensional numerical modeling of flow around the semi-conical piers vertically mounted on the bed in a channel, are presented. For flow simulation, 3-D Navier-Stokes equations are solved numerically using the finite volume method and large eddy simulation (LES). In this study, the semi-conical piers with different side slope angles are tested, and the flow around them is compared with the cylindrical reference pier. Flow structures, vortex shedding behind piers, horseshoe vortices, instantaneous and time-averaged flow structures are presented and discussed. Numerical model results show that the semi-conical piers are eventuated remarkable reduction (up to 25%) in downward flow velocity in the upstream side of the piers, and much more reduction (up to 46%) in bed shear stresses in comparison with the cylindrical pier. Moreover, the model results showed some decrease in vortex shedding frequency for the semi-conical piers compared to the cylindrical pier.We report on numerical results of large eddy simulation of the flow around semi-conical piers with different side slopes. This research is significant because of the effect of these piers on the:reduction of the downward flow and the bed shear stress around the piers.reduction of vortex shedding frequency for the semi-conical piers compared to the cylinder.different behavior of the horseshoe vortices at the upstream compared to the cylinder.

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“…In shallow flow (flow depth <<< channel width) and emergent conditions at the obstacle, a surface standing wave at the junction between the upstream frontal face of the obstacle and the free surface is formed (Boyer & Roy, 1991; Shamloo et al, 2001). This bow wave can affect HV1 as the vortices have opposite direction of rotation (Gazi & Afzal, 2020). With decreasing flow depth, the bow wave dominates and HV1 is less capable of entraining sediment (Melville & Coleman, 2000).…”

Section: Introductionmentioning

confidence: 99%

Geometry of obstacle marks at instream boulders—integration of laboratory investigations and field observations

Schlömer

Grams

Buscombe

et al. 2021

Earth Surf Processes Landf

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Obstacle marks are instream bedforms, typically composed of an upstream frontal scour hole and a downstream sediment accumulation in the vicinity of an obstacle. Local scouring at infrastructure (e.g. bridge piers) is a well-studied phenomenon in hydraulic engineering, while less attention is given to the time-dependent evolution of frontal scour holes at instream boulders and their geometric relations (depth to width, and length ratio). Furthermore, a comparison between laboratory studies and field observations is rare. Therefore, the morphodynamic importance of such scour features to fluvial sediment transport and morphological change is largely unknown. In this study, obstacle marks at boulder-like obstructions were physically modelled in 30 unscaled process-focused flume experiments (runtime per experiment ≥ 5760 min) at a range of flows (subcritical, clear-water conditions, emergent and submerged water levels) and boundary conditions designed to represent the field setting (i.e. obstacle tilting, and limited thickness of the alluvial layer). Additionally, geometries of scour holes at 90 in-situ boulders (diameter ≥ 1 m) located in a 50-km segment of the Colorado River in Marble Canyon (AZ) were measured from a 1 mresolution digital elevation model. Flume experiments reveal similar evolution of local scouring, irrespective of hydraulic conditions, controlled by the scour incision, whereas the thickness of the alluvial layer and obstacle tilting into the evolving frontal scour hole limit incision. Three temporal evolution phases-(1) rapid incision, (2) decreasing incision, and (3) scour widening-are identified based on statistical analysis of spatiotemporal bed elevation time series. A quantitative model is presented that mechanistically predicts enlargement in local scour length and width based on (1) scour depth, (2) the inclination of scour slopes, and (3) the planform area of the frontal scour hole bottom. The comparison of field observations and laboratory results demonstrates scale invariance of geometry, which implies similitude of processes and form rather than equifinality.

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A review on hydrodynamics of horseshoe vortex at a vertical cylinder mounted on a flat bed and its implication to scour at a cylinder

Cited by 26 publications

References 94 publications

Scour at a Submerged Square Pile in Various Flow Depths under Steady Flow

Scour at a Submerged Square Pile in Various Flow Depths under Steady Flow

Large eddy simulation of flow around semi-conical piers vertically mounted on the bed

Geometry of obstacle marks at instream boulders—integration of laboratory investigations and field observations

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