open‐channel flow through simulated vegetation: Suspended sediment transport modeling

López, Fernando Manuel; García, Marcelo H.

doi:10.1029/98wr01922

Cited by 260 publications

(172 citation statements)

References 9 publications

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“…It has long been held that vegetated zones promote particle removal by enhancing residence time (Knight et al 1999) and reducing resuspension (Lopez and Garcia 1998). Indeed, Gacia et al (1999) observed that retention of particles by a seagrass meadow is up to 15 times greater than by barren beds.…”

mentioning

confidence: 99%

Observations of particle capture on a cylindrical collector: Implications for particle accumulation and removal in aquatic systems

Palmer

Nepf

Pettersson

et al. 2004

Limnology & Oceanography

130

232

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Capture of suspended particles by cylindrical collectors is an important mechanism in many aquatic processes, such as larval settlement, suspension feeding, and vegetative filtration. In these processes, the collector Reynolds number (Re c ), based on the collector diameter, ranges from well below 1 to 1,000. No analytical solutions exist to describe capture over most of this range. Capture is typically described by the efficiency, , defined as the ratio of the upstream span of particles that are captured on the collector to the collector diameter. Here, laboratory experiments are used to measure capture efficiency of a single cylinder as a function of Re c and particle ratio, R, which is the ratio of particle diameter to collector diameter. Re c is varied from 50 to 500 and three values of R are used: 0.03, 0.015, and 0.008. The selected particles have a specific gravity of 1.03. For smooth cylinders, capture increases with both Re c and R but is more strongly dependent on R. This result indicates that, in aquatic systems, where flow velocity and suspended particle type and size are fixed, higher capture efficiency will occur on the smallest collectors (those with largest R). Furthermore, we examine a similar experiment in which particles are collected by branched structures. We show that capture to individual cylindrical branches within a compound structure can be predicted by single-cylinder efficiencies. Finally, capture was increased when roughness elements were added to the collectors.

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mentioning

confidence: 99%

Observations of particle capture on a cylindrical collector: Implications for particle accumulation and removal in aquatic systems

Palmer

Nepf

Pettersson

et al. 2004

Limnology & Oceanography

130

232

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“…It acts as an additional source of channel resistance and has been shown to alter bulk flow velocities and conveyance [2][3][4], generate turbulence through coherent flow structures [5][6][7][8], modify sediment transport processes [9][10][11] and increase habitat diversity [12,13]. Therefore, a good process understanding of boundary layer flow through and around vegetation is central in predicting the functioning of the fluvial system.…”

Section: Introductionmentioning

confidence: 99%

Does the canopy mixing layer model apply to highly flexible aquatic vegetation? Insights from numerical modelling

et al. 2016

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Vegetation is a characteristic feature of shallow aquatic flows such as rivers, lakes and coastal waters. Flow through and above aquatic vegetation canopies is commonly described using a canopy mixing layer analogy which provides a canonical framework for assessing key hydraulic characteristics such as velocity profiles, large-scale coherent turbulent structures and mixing and transport processes for solutes and sediments. This theory is well developed for the case of semi-rigid terrestrial vegetation and has more recently been applied to the case of aquatic vegetation. However, aquatic vegetation often displays key differences in morphology and biomechanics to terrestrial vegetation due to the different environment it inhabits. Here we investigate the effect of plant morphology and biomechanical properties on flow-vegetation interactions through the application of a coupled LES-biomechanical model. We present results from two simulations of aquatic vegetated flows: one assuming a semi-rigid canopy and the other a highly flexible canopy and provide a comparison of the associated flow regimes. Our results show that while both cases display canopy mixing layers, there are also clear differences in the shear layer characteristics and turbulent processes between the two, suggesting that the semi-rigid approximation may not provide a complete representation of flow-vegetation interactions.

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“…For regularly-arrayed plants , because the extent of the averaging plane of scheme I is much larger than in scheme II, it can be obtained that <ui>=<ui> and <p>=<p> (Lopez and Garcia 1997). Thus, from Eqs .…”

Section: Averaging Schemesmentioning

confidence: 95%

“…The Reynolds stresses due to spatially fluctuating velocities, < uiuj> , have not been measured so far , so that their relative effect upon the total stress remains still unknown (Lopez and Garcia 1997). If we assume that the flow is steady and fully-developed, then the averaged momentum equation is given by…”

Section: Averaging Schemesmentioning

confidence: 99%

Flow and sediment transport in emerging vegetated zone

Choi

Kang

Yeo

2003

Ecology and Civil Engineering

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Vegetation on the streambed increases the total resistance but decreases the bed shear stress. However, when the drag force term is not separated from the resistance term in the momentum equation, increasing the roughness coefficient due to vegetation may result in increasing the bed shear stress. This is not realistic and crucial to the accurate assess ment of sediment transported in the vegetated zone. This paper presents a 1D model for the simulation of flow and sediment transport in the emerging vegetated zone. The model consists of depth-averaged equations of continuity, momentum, turbulent kinetic energy, and its dissipation rate. The suspended load and bedload are estimated, and the bed elevation change is computed by solving the Exner's equation. The model is validated through com parisons with experimental observations. Then, the model is applied to predict the morpho logical change of the emerging vegetated zone in response to the flood. The developed model can be used to the management of vegetated islands within watercourse made natu rally which are important to river restoration projects nowadays.

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open‐channel flow through simulated vegetation: Suspended sediment transport modeling

Cited by 260 publications

References 9 publications

Observations of particle capture on a cylindrical collector: Implications for particle accumulation and removal in aquatic systems

Observations of particle capture on a cylindrical collector: Implications for particle accumulation and removal in aquatic systems

Does the canopy mixing layer model apply to highly flexible aquatic vegetation? Insights from numerical modelling

Flow and sediment transport in emerging vegetated zone

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