How Different Cross-Sectional Shapes Influence the Separation Zone of an Open-Channel Confluence

Schindfessel, Laurent; Creëlle, Stéphan; Mulder, Tom De

doi:10.1061/(asce)hy.1943-7900.0001336

Cited by 58 publications

(18 citation statements)

References 33 publications

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“…The influence of different cross-sectional shapes on the separation zone in a 90 • open channel confluence was studied by Schindfessel et al (2017) [38]. Four different crosssectional shapes were studied by using large-eddy simulation (LES) model.…”

Section: Asymmetrical Shapedmentioning

confidence: 99%

Review and Comparison of Numerical Simulations of Secondary Flow in River Confluences

Shaheed

Yan

Mohammadian

2021

Water

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River confluences are a common feature in natural water resources. The flow characteristics in confluences are complicated, especially at junction areas between tributaries and the main river. One of the typical characteristics of confluences is secondary flow, which plays an important role in mixing, velocity, sediment transport, and pollutant dispersion. In addition to the experimental and field studies that have been conducted in this area, the development of computational fluid dynamics has allowed researchers in this field to use different numerical models to simulate turbulence properties in rivers, especially secondary flows. Nowadays, the hydrodynamics of flows in confluences are widely simulated by using three-dimensional models in order to fully capture the flow structures, as the flow characteristics are considered to be turbulent and three-dimensional at river junctions. Several numerical models have been recommended for this purpose, and various turbulence models have been used to simulate the flows at confluences. To assess the accuracy of turbulence models, flows have been predicted by applying different turbulence models in the numerical model and the results have been compared with other data, such as field, laboratory, and experimental data. The purpose behind these investigations was to find the suitable model for each case of turbulent flow and for different types of confluences. In this study, the performances of turbulence models for confluences are reviewed for different numerical simulation strategies.

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Section: Asymmetrical Shapedmentioning

confidence: 99%

Review and Comparison of Numerical Simulations of Secondary Flow in River Confluences

Shaheed

Yan

Mohammadian

2021

Water

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“…Different techniques were employed in the past for accurately determining the separation zone (e.g., [15,20]). However, since this is a region of decreased downstream momentum, the delineation of the separation zone extension is not an easy task.…”

Section: Computational Domain and Validation Of The Numerical Modelmentioning

confidence: 99%

“…The contraction coefficient can be used for the determination of the head losses (∆h L ) at junctions with the Borda-Carnot formula for a sudden flow expansion (e.g., [15]) as (1…”

Section: Contraction Zone and Maximum Streamwise Velocitymentioning

confidence: 99%

“…Subsequently, the determination of the shape and the extent of the separation zone has become the main objective of the research in the field of open-channel confluences, owing to its importance in (1) confining the effective width of the post-confluence channel towards the opposite wall of the junction, giving rise to the adjacent zone of maximum velocity and bed shear stress, and (2) in the overall head losses at junctions, as well as sediment and solute balances [15]. For instance, through vertical photography of surface dye traces, Best and Reid [16] showed that the width and length of the flow separation zone increases with both α and the discharge ratio.…”

Section: Introductionmentioning

confidence: 99%

“…The changed flow patterns also influence the mixing layer and the flow recovery. In their successive work, Schindfessel et al [15] analysed the influence of the cross-sectional shape on the flow patterns in a 90 • confluence. They showed that the shape of the cross-section, and more particularly the geometry of the downstream corner, can induce lateral currents directed into the separation zone.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Effect of the Junction Angle on Turbulent Flow at a Hydraulic Confluence

Penna

Marchis

Canelas

et al. 2018

Water

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Despite the existing knowledge concerning the hydrodynamic processes at river junctions, there is still a lack of information regarding the particular case of low width and discharge ratios, which are the typical conditions of mountain river confluences. Aiming at filling this gap, laboratory and numerical experiments were conducted, comparing the results with literature findings. Ten different confluences from 45 • to 90 • were simulated to study the effects of the junction angle on the flow structure, using a numerical code that solves the 3D Reynolds Averaged Navier-Stokes (RANS) equations with the k-turbulence closure model. The results showed that the higher the junction angle, the wider and longer the retardation zone at the upstream junction corner and the separation zone, and the greater the flow deflection at the entrance of the tributary into the post-confluence channel. Furthermore, it was shown that the maximum streamwise velocity does not necessarily increase with the junction angle and that it is not always located in the contraction section.

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Experimental Investigation of Free Surface Gradients in a 90° Angled Asymmetrical Open Channel Confluence

Creëlle

Engelen

Schindfessel

et al. 2018

Advances in Hydroinformatics

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How Different Cross-Sectional Shapes Influence the Separation Zone of an Open-Channel Confluence

Cited by 58 publications

References 33 publications

Review and Comparison of Numerical Simulations of Secondary Flow in River Confluences

Review and Comparison of Numerical Simulations of Secondary Flow in River Confluences

Effect of the Junction Angle on Turbulent Flow at a Hydraulic Confluence

Experimental Investigation of Free Surface Gradients in a 90° Angled Asymmetrical Open Channel Confluence

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