Three-dimensional numerical simulation of flow around stream deflectors: The effect of obstruction angle and length

Haltigin, T.; Biron, Pascale M.; Lapointe, Martine-Emmanuelle

doi:10.1080/00221686.2007.10525038

Cited by 20 publications

(14 citation statements)

References 18 publications

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“…The model is described in detail elsewhere (Bradbrook et al ., 1998) and has been used extensively in both laboratory (Bradbrook et al ., 2001) and field studies (Ferguson et al ., 2003; Carré et al ., 2006). All simulations were performed using the RNG k‐ε turbulence model, previously shown to perform well for simulation of flows in areas affected by high shear (Richardson and Panchang, 1998) such as regions of significant separation and recirculation (Ferguson et al ., 2003), as is the case near deflectors (Haltigin et al ., 2007) and near bendway weirs (Abad et al , 2008). Water surface representation was achieved using the variable porosity approach in the surface layer cell (Ouillon and Dartus, 1997; Bradbrook et al ., 1998; Biron et al ., 2002).…”

Section: Methodsmentioning

confidence: 99%

“…It has thus not been possible to validate the model at high flow when deflectors are submerged. However, this model has been used successfully in complex environments such as around laboratory flow deflectors (Haltigin et al ., 2007) and river confluences (Bradbrook et al ., 2000; Biron et al ., 2004a); we thus believe that it can generate reliable results at higher flow stage, at least in terms of overall spatial patterns of velocity. Nevertheless, lack of validation at high flow is a limitation of this study which calls for caution in the interpretation of results from these simulations.…”

Section: Methodsmentioning

confidence: 99%

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Sediment Transport and Flow Dynamics Around a Restored Pool in a Fish Habitat Rehabilitation Project: Field and 3d Numerical Modelling Experiments

Biron

Carver

Carré

2011

River Research & Apps

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Few studies have examined sediment transport patterns around in-stream structures used to enhance fish habitat despite the importance of this variable in the successful design of stream restoration schemes. The objective of this study is to examine interactions between the (excavated) pool morphology, flow and sediment transport in a restored reach of the Nicolet River (Quebec, Canada). Bedload transport was investigated using passive integrated transponder (PIT) tagged particles that were followed from positions upstream of a pair of current deflectors which were designed to maintain the excavated pool downstream. Three-dimensional numerical simulations of the flow field at various flow stages (with emerged or submerged deflectors) were used to relate near-bed velocity and bed shear stress to transport patterns and to assess the impact of varying the pool location and geometry on the flow field and water surface profiles. Results show that from 2005 to 2008, of the 117 pit-tagged particles that fell in the pool, only 27 are known to have exited. None of the 30 largest rocks entering the pool escaped. Bed shear stress values simulated at high and peak flow (slightly above bankfull level) are not sufficient to move the largest rocks in the pool exit zone. Simulations also reveal a complex water surface topography when flow is above the height of deflectors, with negative water surface slope in the pool zone. When modifying the pool geometry so that the deepest zones are close to the apex of the in-stream structures instead of in the centre of the channel, both water surface slope and near-bed velocity patterns are greatly modified. Understanding the interactions between excavated pools, bedload and 3D velocity patterns around in-stream structures is essential for long-term success of fish habitat restoration projects, and using 3D models to test various designs of artificial pools is a promising approach. Figure 2. (a) Location map of the Nicolet watershed; (b) field site location within the Nicolet watershed (black triangle); the grey zone represents the Appalachian part of the watershed, whereas the white area is located in the St. Lawrence Lowlands; (c) photograph showing the upstream and downstream paired deflectors at the field site; (d) bed topography showing the downstream excavated pool and the upstream pressure transducer (indicated by a black star).This figure is available in colour online at wileyonlinelibrary.com/journal/rra

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Sediment Transport and Flow Dynamics Around a Restored Pool in a Fish Habitat Rehabilitation Project: Field and 3d Numerical Modelling Experiments

Biron

Carver

Carré

2011

River Research & Apps

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“…Recent work is notable for introducing concepts and methods of hydraulic design for creating stable riffle structures in steep, gravel channels (Walker et al, 2004; and assessment of the performance of in-stream structures such as flow deflectors, groynes or large wood (Biron et al, 2004;Lacey and Millar, 2004). A combination of field studies (Champoux et al, 2003;Walker et al, 2004;Carré et al, 2007), laboratory experiments (Matsuura and Townsend, 2004;Biron et al, 2004;, and numerical flow and habitat simulations in 2D (Katopodis, 2003;Lacey and Millar, 2004) or 3D (Carré et al, 2006;Haltigin et al, 2007) have provided a much needed fundamental understanding of the impacts of restoration projects on physical habitat in a field that is often based on trial and error.…”

Section: Eco-hydraulics and Eco-geomorphologymentioning

confidence: 98%

Recent Canadian Research on Fluvial Sediment Transport and Morphology, 2003-2007

Ashmore¹,

Biron²,

Eaton³

et al. 2009

Canadian Water Resources Journal

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Review of recent research on river dynamics in Canada reveals a diverse, active and growing research community engaged in fundamental research at all scales and motivated by a concern for understanding the Canadian landscape, the impacts of development and resource activities and concerns for environmental quality. Several research groups and collaborative programs (national and international), and many individual researchers have made significant progress in areas such as fluvial turbulence, sand bedforms, eco-geomorphology, gravel-bed river morpho-dynamics, regime analysis, numerical modelling of fluvial dynamics and fine-sediment erosion and transport, all supported by new developments in instrumentation and remote sensing applications.Résumé : Un examen des recherches récentes sur la dynamique des rivières au Canada révèle l'existence d'une collectivité de recherche diversifiée, active et croissante, engagée dans la recherche fondamentale à toutes les échelles et motivée par la volonté de comprendre le paysage canadien, les incidences du développement et des activités relatives aux ressources, ainsi que les préoccupations entourant la qualité de l'environnement. Plusieurs groupes de recherche et programmes axés sur la collaboration (nationaux et internationaux) et de nombreux chercheurs individuels ont accompli des progrès considérables dans des domaines comme la turbulence fluviale, la formation de lits de sable, l'éco-géomorphologie, la morphodynamique des rivières à lits de gravier, l'analyse du régime, la modélisation numérique de la dynamique fluviale et l'érosion et le transport des sédiments fins, domaines de recherche qui reposent tous sur de nouveaux développements en matière d'instrumentation et d'applications de télédétection.

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“…The morphology dynamics, including scour and deposition at the toe of submerged rigid engineering structures, such as engineering deflectors, have attracted substantial research. Most of this research has focused on the developing process of local scour and the local flow pattern [5][6][7][8], the scour depth and the scour volume [9][10][11], the temporal development of scour hole [12], and the sediment deposition features [13].…”

Section: Introductionmentioning

confidence: 99%

Local Scour Near Flexible Flow Deflectors

Xie

Zhu

Huang

et al. 2020

Water

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Rigid flow deflectors are usually used on water flow beds to protect engineering structures such as breakwater in coasts and to regulate flow routes in open channels. To reduce its side-effects, i.e., local scour at the toe of deflectors, a flexible flow deflector is proposed, and the corresponding local scour was investigated in this study. A flume experiment was conducted to investigate local scour. To show the advantage of flexible deflectors, a control experimental test was also conducted using a traditional rigid deflector under the same blockage area configuration and the same flow conditions. The flow field near the flexible deflector was also measured to reveal the local flow field. The results show that the bed-scour develops near the toe edges of both flexible and rigid deflectors, but the maximum and averaged scour depths for the flexible deflector are smaller. This advantage of flexible deflector in scour depth is mainly caused by its prone posture, which induces the upward stretching and enlarging horizontally rotating vortex and the upward shifted vertically rotating vortex. The former dissipates more turbulent energy and the latter results in smaller bed shear stress, which lead to smaller scour depth directly. In addition, the up- and down-swaying movement of the flexible deflector can also assistant to dissipate more turbulent energy, thereby damping the intense of the horseshoe vortices and thus weakening scour depth as well. The results of this study provide an elementary understanding on the mechanisms of a flexible flow structure and an alternative deflector-device to reduce scour depth.

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Three-dimensional numerical simulation of flow around stream deflectors: The effect of obstruction angle and length

Cited by 20 publications

References 18 publications

Sediment Transport and Flow Dynamics Around a Restored Pool in a Fish Habitat Rehabilitation Project: Field and 3d Numerical Modelling Experiments

Sediment Transport and Flow Dynamics Around a Restored Pool in a Fish Habitat Rehabilitation Project: Field and 3d Numerical Modelling Experiments

Recent Canadian Research on Fluvial Sediment Transport and Morphology, 2003-2007

Local Scour Near Flexible Flow Deflectors

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