Numerical simulations of turbulent flow around side-by-side circular piles with different spacing ratios

Beheshti, Aliasghar; Ataie-Ashtiani, Behzad; Dashtpeyma, Hamed

doi:10.1080/15715124.2017.1280811

Cited by 3 publications

(2 citation statements)

References 46 publications

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“…Positive values of

\mathbf{Q}

occur where

{{\Omega }}_{ij}{{\Omega }}_{ij}

exceeds

{S}_{ij}{S}_{ij}

, which indicates the presence of rotational flow or vortices. The

\mathbf{Q}

‐criterion has been used in several hydrodynamic and geomorphological studies to identify and describe vortices in channel confluences, around groynes, and in channel bends (Beheshti et al., 2017; Ettema et al., 2017; Guillén Ludeña et al., 2017; Keylock et al., 2016).…”

Section: Methodsmentioning

confidence: 99%

Plunging Flow and Coherent Turbulent Structures in a Straight Pool‐Riffle

Dashtpeyma

MacVicar

2023

JGR Earth Surface

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Riffle-pools are a commonly observed undulating bed morphology in gravel-bed rivers, with the deeper areas of the river called pools and the shallower parts called riffles (D. M. Thompson & MacVicar, 2022). Researchers have observed a range of hydraulic phenomena at field sites with this morphology that are not seen in more uniformly shaped channels. One of the earliest observations, for example, noted a rapid increase in near bed velocity in a pool as flood stage increased and proposed a "velocity reversal" hypothesis in which the near bed velocity in the pool was thought to exceed that in the riffle at high flood stages (Keller, 1971). If observed in other pools, this mechanism would have provided a simple physical explanation for pool scour and maintenance, but field measurement of this mechanism is challenging and evidence has been mixed (Byrne et al., 2021;Clifford & Richards, 1992;Milan, 2013). As instrumentation improved, it became possible to measure turbulent fluctuations. Researchers noted high turbulent intensities and sometimes highly coherent turbulent structures, which led them to consider ways in which turbulent scour might impact pool formation (

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“…Positive values of

\mathbf{Q}

occur where

{{\Omega }}_{ij}{{\Omega }}_{ij}

exceeds

{S}_{ij}{S}_{ij}

, which indicates the presence of rotational flow or vortices. The

\mathbf{Q}

Section: Methodsmentioning

confidence: 99%

Plunging Flow and Coherent Turbulent Structures in a Straight Pool‐Riffle

Dashtpeyma

MacVicar

2023

JGR Earth Surface

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“…The development of CFD models motivated the use of numerical simulations [22][23][24][25][26]. No agreement among researchers has been achieved regarding the appropriate turbulence model for the numerical simulation of the flow structures and the bed shear stress around the bridge piers.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Numerical Investigations of the Flow Pattern and Evolution of the Horseshoe Vortex at a Circular Pier during the Development of a Scour Hole

Helmi

Shehata

2021

Applied Sciences

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In the current study, a three-dimensional CFD model is utilized to investigate the variation of the flow structure and bed shear stress at a single cylindrical pier during scour development. The scour development is presented by seven solidified geometries of the scour hole, collected during previous experimental work at different scour stages. Different turbulence models are evaluated and the (k-ω) model is chosen due to its relative accuracy in capturing the flow oscillation and vortex shedding at the pier downstream side with personal computer computational and storage resources. The numerical results are verified against dimensionless parameters from different previous experimental works. This research describes in detail the flow structure and bed shear stress variations through seven stages of the scour hole development. The dimensionless area-averaged circulation coefficient (Ψi) is developed to evaluate the changes in the vortex strength through the scouring process by eliminating the calculation area effect. It was concluded that the circulation in the (Y) direction is the main driving factor in the development of the scour hole more than the circulation in the (X) direction. The ratio between the horseshoe vortex (HV) mean size and the scouring depth (DV/dS) in addition to the location of the maximum bed shear stress are investigated during different stages of the scour development.

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