Permeability effects of single groin on flow characteristics

Kang, Joongu; Yeo, Hongkoo; Kim, Sungjung; Ji, Un

doi:10.1080/00221686.2011.614520

Cited by 41 publications

(31 citation statements)

References 14 publications

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“…For 2aW v /W ≥ 5.0 and 2W v /W ≥ 0.4, the scour pool is created between the paired obstructions and maximum scour depth always takes place at the scour pool. For 2aW v /W ≥ 5.0 and 2W v /W ≥ 0.4, the flow accelerates between the porous obstructions and the flow becomes greater with an increase in the flow blockage, which is related to a flow diversion [11,12,18]. When the flow blockage increases, the diverging flow from the porous obstructions increases due to higher drag, leading to greater magnitude of the velocity and turbulence at the center of the channel.…”

Section: Scour Poolmentioning

confidence: 99%

“…Preliminary 12-h tests for three cases (Exp No. 4,5,12) were carried out to determine the duration of experimental runs (Figure 3). The result showed that approximately 95% of the maximum scour depth (d s ) normalized by scour depth value at the end of the runs (d se ) was achieved at t/t e = 0.7, where t is the time and t e is the steady state time.…”

Section: Methodsmentioning

confidence: 99%

“…Rodrigue-Gervais et al [4] obtained predictive equations for depth and volume of scour pools associated with paired structures. Kang et al [12] investigated flow patterns around single spur dikes and permeability effects. Nepf [13] showed some results of flow characteristics around single porous structures and examined the effect of submergence ratio and density on flow fields and sediment transport.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigations of Scour Pools around Porous Obstructions

Kim

Kimura

Shimizu

2016

Water

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Paired impermeable or porous obstructions are used to create scour pool habitat. We investigated local scour pools created by paired porous obstructions using laboratory experiments. To examine the influence of porous obstructions on local scour depths and volumes, various densities in the porous obstructions, ratio of obstruction width to channel width and submergence ratio were evaluated. A local scour pool developed when the flow blockage (product of density in the porous obstructions and ratio of obstruction width to channel width) and the ratio of the obstruction width to channel width were ≥5.0 and ≥0.4, respectively. The depth of the scour pool increased with increasing flow blockage, while scour depth reduced as the submergence ratio increased. The scoured volume had a strong relationship with the scour depth around the porous obstructions. Results of the predictive equations were considered reliable for estimating the maximum scour depth and scoured volume around porous obstructions in clear-water conditions.

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Section: Scour Poolmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Investigations of Scour Pools around Porous Obstructions

Kim

Kimura

Shimizu

2016

Water

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“…However, spur-type structures experienced frequent and severe damage compared to other high-cost river training structures, e.g., long embankments, due to the dynamic characteristics of the river and instability of the flows (governed by local scouring) induced by the structures [6,7]. Around the world, previous studies documented the use of spur dikes in rivers to provide adequate depth, mitigate bank erosion, and improve land reclamation and ecological richness by creating stagnant zones [4,6,[8][9][10][11][12][13][14][15][16][17][18]. However, field observations and multiple laboratory studies have revealed relatively large scour holes produced by impermeable spur dike fields.…”

Section: Introductionmentioning

confidence: 99%

“…However, field observations and multiple laboratory studies have revealed relatively large scour holes produced by impermeable spur dike fields. Angled flows, bedform movement, and rapid siltation or erosion downstream create favorable conditions for local scouring [7,8,[16][17][18][19][20][21][22][23] Therefore, a detailed understanding of the flow around such structures is crucial for the optimum design of spur dikes to manage this type of dynamic river.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Flow Characteristics in Slit-Type Permeable Spur Dike Fields: Efficacy in Riverbank Protection

Shampa

Hasegawa

Nakagawa

et al. 2020

Water

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This paper focuses on finding efficient solutions for the design of a highly permeable pile spur (or slit type) dike field used in morphologically dynamic alluvial rivers. To test the suitability of different arrangements of this type of permeable pile spur dike field, laboratory experiments were conducted, and a three-dimensional multiphase numerical model was developed and applied, based on the experimental conditions. Three different angles to the approach flow and two types of individual pile position arrangements were tested. The results show that by using a series of slit-type spurs, the approach velocity of the flow can be considerably reduced within the spur dike zone. Using different sets of angles and installation positions, this type of permeable spur dike can be used more efficiently than traditional dikes. Notably, this type of spur dike can reduce the longitudinal velocity, turbulence intensity, and bed shear stress in the near-bank area. Additionally, the deflection of the permeable spur produces more transverse flow to the opposite bank. Arranging the piles in staggered grid positions among different spurs in a spur dike field improves functionality in terms of creating a quasi-uniform turbulence zone while simultaneously reducing the bed shear stress. Finally, the efficacy of the slit-type permeable spur dike field as a solution to the riverbank erosion problem is numerically tested in a reach of a braided river, the Brahmaputra–Jamuna River, and a comparison is made with a conventional spur dike field. The results indicate that the proposed structure ensures the smooth passing of flow compared with that for the conventional impermeable spur structure by producing a lower level of scouring (low bed shear stress) and flow intensification.

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