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

Penna, Nadia; Marchis, Mauro De; Canelas, Olga Birjukova; Napoli, Enrico; Cardoso, António H.; Gaudio, Roberto

doi:10.3390/w10040469

Cited by 56 publications

(18 citation statements)

References 38 publications

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“…This fact is ascribed to the acceleration induced by the lateral flow that approaches the post-confluence channel. Furthermore, it is also evidenced that the higher the θ, the more extended the retardation zone and the lower the velocities in this region [95].…”

Section: Confluence Planformmentioning

confidence: 86%

“…Ashmore and Parker [78] described this effect as a decrease in curvature radius, where a higher θ causes the flows of the two tributaries to pass through with enhanced turbulence. Penna et al found that the maximum streamwise flow velocity does not necessarily increase with the θ, and it does not always occur in the contraction zone [95]. This fact is ascribed to the acceleration induced by the lateral flow that approaches the post-confluence channel.…”

Section: Confluence Planformmentioning

confidence: 99%

See 1 more Smart Citation

Flow, Sediment, and Morpho-Dynamics of River Confluence in Tidal and Non-Tidal Environments

Bilal

Xie

Zhai

2020

JMSE

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River confluences are the key features of the drainage basins, as their hydrological, geomorphological, and ecological nature strongly influences the downstream river characteristics. The river reaches near the coastal zones, which also makes them under the influence of tidal currents in addition to their runoff. This causes a bi-directional flow and makes the study of confluences more interesting and complex in these areas. There is a reciprocal adjustment of flow, sediment, and morphology at a confluence, and its behaviors, differ greatly in tidal and non-tidal environments. Existing studies of the river junctions provide a good account of information about the hydrodynamics and bed morphology of the confluent areas, especially the unidirectional ones. The main factors which affect the flow field include the angle of confluence, flow-related ratios (velocity, discharge, and momentum) of the merging streams, and bed discordance. Hydraulically, six notable zones are identified for unidirectional confluences. However, for bi-directional (tidal) junctions, hydrodynamic zones always remain in transition but repeat in a cycle and make four different arrangements of flow features. This study discusses the hydrodynamics, sediment transport, morphological changes, and the factors affecting these processes and reviews the recent research about the confluences for these issues. All of these studies provide insights into the morpho-dynamics in tidal and non-tidal confluent areas.

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Section: Confluence Planformmentioning

confidence: 86%

Section: Confluence Planformmentioning

confidence: 99%

Flow, Sediment, and Morpho-Dynamics of River Confluence in Tidal and Non-Tidal Environments

Bilal

Xie

Zhai

2020

JMSE

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“…Nadia el al. [14], with their experimental work, found 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.…”

Section: Introductionmentioning

confidence: 88%

Hydraulic Features of Flow through Local Non-Submerged Rigid Vegetation in the Y-Shaped Confluence Channel

Tong

Liu

Yang

et al. 2019

Water

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A laboratory measurement with acoustic Doppler velocimeter (ADV) was used to investigate the flow through a Y-shaped confluence channel partially covered with rigid vegetation on its inner bank. In this study, the flow velocities in cases with and without vegetation were measured by the ADV in a Y-shaped confluence channel. The results clearly showed that the existence of non-submerged rigid plants has changed the internal flow structure. The velocity in the non-vegetated area is greater than in the vegetated area. There is a large exchange of mass and momentum between the vegetated and non-vegetated areas. In addition, due to the presence of vegetation, the high-velocity area moved rapidly to the middle of the non-vegetated area in the vicinity of tributaries, and the secondary flow phenomenon disappeared. The presence of vegetation made the flow in non-vegetated areas more intense. The turbulent kinetic energy of the non-vegetated area was smaller than that of the vegetated area.

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“…Although many studies on junction angles have been done up until now (Best and Rhoads, 2008;Santos and Stevaux, 2017), knowledge about its formation and determination still maintains strong interest (Hooshyar et al, 2017;Alomari et al, 2018;Yukawa et al, 2019). However, the majority of the studies in this topic is directed to the understanding of the flow regime, of the interactions that occur inside the channel, and of the sediment mobility of the channels (Park and Latrubesse, 2015;Penna et al, 2018;Herrero et al, 2018;Dixon et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Determination of the junction angle in fluvial channels from georeferenced aerial images from Google Earth Pro and UAV

Pereira¹,

Barbieiro²,

Carneiro³

et al. 2019

Rev. ambiente água

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The junction angles in fluvial channels are determined from complex erosion and deposition processes, resulting from river-flow dynamics, bed and margin morphology, and so on. Knowledge regarding these angles is important in order to better understand the existing conditions in a basin. In this sense, the objective of the present study was to determine the junction angles on fluvial channels, called α, β and γ, applying the law of cosines. Georeferenced Google Earth Pro images and UAV images were used. Then, the values calculated from the georeferenced aerial images were compared with the values calculated from the minimum energy principle. To visualize and understand the obtained angles, the Junction Angles Diagram was used. The obtained result shows that the methodology using georeferenced aerial images have good performance for determining junction angles on fluvial channels.

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

Cited by 56 publications

References 38 publications

Flow, Sediment, and Morpho-Dynamics of River Confluence in Tidal and Non-Tidal Environments

Flow, Sediment, and Morpho-Dynamics of River Confluence in Tidal and Non-Tidal Environments

Hydraulic Features of Flow through Local Non-Submerged Rigid Vegetation in the Y-Shaped Confluence Channel

Determination of the junction angle in fluvial channels from georeferenced aerial images from Google Earth Pro and UAV

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