On why and how do rivers meander

Silva, A.M. Ferreira Da

doi:10.1080/00221686.2006.9521708

Cited by 59 publications

(7 citation statements)

References 16 publications

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“…For the tests without cylindrical rods, the results indicated that erosion takes place close to the outer bank between cross-section C1 and the middle of the test section (cross-section C3), while deposition occurs adjacent to the inner bank from the center of the test section to cross-section C5 (Figure 3a). The above results are consistent with previous studies [22,[53][54][55]. Regarding the pattern of eroded and deposited regions, the results are also consistent with the findings of da Silva [55] and da Silva and Yalin [53], who showed that at the inward bank of the rivers with ingoing meanders, the current accelerates from the entrance to the vertex, while it slows down from the vertex to the curve exit, as will be discussed in the next sections in this paper.…”

Section: Bed Topographysupporting

confidence: 94%

“…The above results are consistent with previous studies [22,[53][54][55]. Regarding the pattern of eroded and deposited regions, the results are also consistent with the findings of da Silva [55] and da Silva and Yalin [53], who showed that at the inward bank of the rivers with ingoing meanders, the current accelerates from the entrance to the vertex, while it slows down from the vertex to the curve exit, as will be discussed in the next sections in this paper. However, for SR and DR models, maximum deposition occurred close to the outside bank in the center of the test section, i.e., the bend apex (Figure 3b) which may be related to the reduced turbulence due to the diverted flow by the rods.…”

Section: Bed Topographysupporting

confidence: 94%

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Influence of Rigid Emerged Vegetation in a Channel Bend on Bed Topography and Flow Velocity Field: Laboratory Experiments

Hamidifar

Keshavarzi

Rowiński

2019

Water

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Trees have been used extensively by river managers for improving the river environment and ecology. The link between flow hydraulics, bed topography, habitat availability, and organic matters is influenced by vegetation. In this study, the effect of trees on the mean flow, bed topography, and bed shear stress were tested under different flow conditions. It was found that each configuration of trees produced particular flow characteristics and bed topography patterns. The SR (single row of trees) model appeared to deflect the maximum velocity downstream of the bend apex toward the inner bank, while leading the velocity to be more uniformly distributed throughout the bend. The entrainment of sediment particles occurred toward the area with higher values of turbulent kinetic energy (TKE). The results showed that both SR and DR (double rows of trees) models are effective in relieving bed erosion in sharp ingoing bends. The volume of the scoured bed was reduced up to 70.4% for tests with trees. This study shows the effectiveness of the SR model in reducing the maximum erosion depth.

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Section: Bed Topographysupporting

confidence: 94%

Section: Bed Topographysupporting

confidence: 94%

Influence of Rigid Emerged Vegetation in a Channel Bend on Bed Topography and Flow Velocity Field: Laboratory Experiments

Hamidifar

Keshavarzi

Rowiński

2019

Water

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“…After the seminal paper by Langbein and Leopold [23], SG curves became a standard model to describe river meanders, widely employed in hydrology-related fields [24][25][26]. In this paper, we show how SG curves naturally appear in a very different context, specifically in the study of the surface-diffusion-driven decay of high-aspect-ratio (HAR) 1 patterned surfaces, but we also show the kinetic evolution of the parameters that describe the SG curve.…”

Section: Introductionmentioning

confidence: 96%

One-dimensional gratings evolving through high-temperature annealing: sine-generated solutions

Madrid

Salvarezza

Castez

2011

J. Phys.: Condens. Matter

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Sine-generated curves (i.e. curves in which the curvature is a sine function of the arc-length parameter) have been used in the past to describe river meanders. Here we show how these curves spontaneously appear during the decay of high-aspect-ratio surfaces mediated by surface diffusion. We obtained analytical results for the kinetic evolution of such processes relevant to a wide class of initial geometries. Our theoretical results were satisfactorily compared with numerical simulations and with results from previous approaches to the same problem, and they can be useful for interpreting and designing experiments related to the technologically important process of high-temperature annealing on nano/micro-structured samples.

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“…The banks of river bends are most vulnerable to scouring, therefore enhanced protection is required for restoration. Recent research by, for example, Ferreira da Silva (2006), Abad and Garcia (2009), Chen and Tang (2012), Engel and Rhoads (2012), and Keshavarzi (2011, 2013) has highlighted the importance of river restoration techniques for river management. However, little is known about bank dynamics in meandering rivers and its implications for meander migration.…”

Section: Introductionmentioning

confidence: 99%

“…When λ = λ c , neither erosion nor deposition occur leading to a neutrally stable equilibrium. It has been shown that, in order to decrease erosion at the near-bank bed, counter-rotating vortices may be used to lessen the secondary flow (Tominaga et al 1999, Ferreira da Silva 2006. Ashida et al (1989) investigated bed variations in a meandering channel with sinuosity equal to 1.17.…”

Section: Introductionmentioning

confidence: 99%

Bed morphology in vegetated estuarine river with mild-curved meander bend

Keshavarzi

Hamidifar

Ball

2016

Hydrological Sciences Journal

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In this study, the effect of single and double row piles for reducing scouring in a mild-curved river meander was studied experimentally. The experimental study focused on the effect of vegetation on bed topography in a mild-curved meander bend. The experimental tests were conducted in a laboratory flume under clear water flow conditions. A series of experimental tests were carried out with a fixed bed and non-vegetated and vegetated moveable beds with different vegetation patterns. Analysis of the flow characteristics indicated that when the bed was mobile with vegetation on the inner bank, the core of maximum streamwise velocity shifted towards the centreline of the bend. Additionally, the cross-sectional kinetic energy increased from 0.05% for the fixed-bed test to 4.30% for the test with a double row of vegetation. Furthermore, the presence of vegetation was found to increase the uniformity of the distribution of turbulence intensity and to reduce the Reynolds shear stress along the test section. Also, the mass fluxes increased from the outer bank to the inner bank and from the upstream towards the downstream of the bend. Finally, comparison of bed topography in vegetated and nonvegetated channels showed that the maximum scour depth at the bend apex was reduced by 77% and 62% for the cases with one row and two rows of vegetation, respectively. The results of this study were compared with previously proposed models for predicting the vertical distribution of the streamwise velocity at the bend apex. It was found that Johannesson and Parker's model (JPM) gave the lowest value of standard error. The above findings are useful in river training works and, in particular, for restoration of meandering rivers.

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On why and how do rivers meander

Cited by 59 publications

References 16 publications

Influence of Rigid Emerged Vegetation in a Channel Bend on Bed Topography and Flow Velocity Field: Laboratory Experiments

Influence of Rigid Emerged Vegetation in a Channel Bend on Bed Topography and Flow Velocity Field: Laboratory Experiments

One-dimensional gratings evolving through high-temperature annealing: sine-generated solutions

Bed morphology in vegetated estuarine river with mild-curved meander bend

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