A numerical model for flow in meandering channels with natural bed topography

The present book covers topics both on fluvial and lagoon morphodynamics. The first part is dedicated to tidal environments. Topics include an overview of main morphological features and mechanisms of estuaries and tidal channels and a model devoted to investigate flow field pattern and bed topography in tidal meandering channels and a comparison with recent observational evidence of meanders within different tidal environments. The general failure of Bagnold hypothesis when applied to equilibrium bedload transport at even relatively modest transverse slope is demonstrated. A new model is then proposed based on an empirical entrainment formulation of bed grains.

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Construction and Validation of a Numerical Model of a Reservoir Consisting of Meandering Channels

SPE Reservoir Engineering ◽

10.2118/25057-pa ◽

1994 ◽

Vol 9 (01) ◽

pp. 9-14

Author(s):

W. van Vark ◽

A.H.M. Paardekam ◽

J.F. Brint ◽

J.B. van Lieshout ◽

P.M. George

Keyword(s):

Numerical Model ◽

Meandering Channels

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ABSTRACT: Flow Structure and Bed Topography in Submarine Meandering Channels

AAPG Bulletin ◽

10.1306/8626e23d-173b-11d7-8645000102c1865d ◽

2001 ◽

Vol 85 ◽

Author(s):

Jasim Imran1, Ahmed Kassem1

Keyword(s):

Flow Structure ◽

Bed Topography ◽

Meandering Channels

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Experiments on Longitudinal and Transverse Bedload Transport in Sine-Generated Meandering Channels

Applied Sciences ◽

10.3390/app11146560 ◽

2021 ◽

Vol 11 (14) ◽

pp. 6560

Author(s):

Li He ◽

Dong Chen ◽

Donatella Termini ◽

Shiyan Zhang ◽

Zhenhui Zhu

Keyword(s):

Longitudinal Direction ◽

Bedload Transport ◽

Bed Topography ◽

Bed Deformation ◽

Meandering Channels ◽

Curved Channels ◽

Initial Location ◽

Moving Direction ◽

Point Bars ◽

Gain Loss

Bedload grains in consecutive meandering bends either move longitudinally or across the channel centerline. This study traces and quantifies the grains’ movement in two laboratorial sine-generated channels, i.e., one with deflection angle θ0 = 30° and the other 110°. The grains originally paved along the channels are uniform in size with D = 1 mm and are dyed in various colors, according to their initial location. The experiments recorded the changes in the flow patterns, bed deformation, and the gain-loss distribution of the colored grains in the pool-bar complexes. We observed the formation of two types of erosion zones during the process of the bed deformation, i.e., Zone 1 in the foreside of the point bars and Zone 2 near the concave bank downstream of the bend apexes. Most grains eroded from Zone 1 are observed moving longitudinally as opposed to crossing the channel centerline. Contrastingly, the dominant moving direction of the grains eroded from Zone 2 changes from the longitudinal direction to the transversal one as the bed topography evolves. Besides, most building material of the point bars comes from the upstream bends, although low- and highly curved channels behave differently.

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Assessing different methods of generating a three-dimensional numerical model mesh for a complex stream bed topography

International Journal of Computational Fluid Dynamics ◽

10.1080/10618560701374411 ◽

2007 ◽

Vol 21 (1) ◽

pp. 37-47 ◽

Cited By ~ 8

Author(s):

Pascale M. Biron ◽

Timothy W. Haltigin ◽

Richard J. Hardy ◽

Michel F. Lapointe

Keyword(s):

Numerical Model ◽

Three Dimensional ◽

Bed Topography ◽

Stream Bed

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Numerical simulation of sediment transport in a U-shaped channel with lateral intake: Effects of intake position and diversion angle

International Journal of Modern Physics C ◽

10.1142/s0129183119500712 ◽

2019 ◽

Vol 30 (09) ◽

pp. 1950071 ◽

Cited By ~ 1

Author(s):

Keivan Tavakoli ◽

Hossien Montaseri ◽

Pourya Omidvar ◽

Stefania Evangelista

Keyword(s):

Sediment Transport ◽

Numerical Model ◽

Transport Mechanism ◽

Discrete Phase Model ◽

Reference Time ◽

Bed Topography ◽

Discharge Ratio ◽

Discrete Phase ◽

Sediment Particles ◽

Good Agreement

In this work, the mechanism of sediment transport in a U-shaped channel with a lateral intake is investigated experimentally and numerically, together with the processes of sediment entry into the intake itself and formation of bed topography. Dry sediment is injected into a steady flow in a rigid channel with a bend and sediment particles are traced in time. In order to validate the numerical model, the three components of the flow velocity, as well as the sediment path in time and the diverted sediment ratios, are measured experimentally. A numerical Discrete Phase Model (DPM) is then applied to study the effect of the intake position and diversion angle on the sediment transport mechanism in the bend. The DPM has, in fact, the capability of specifying for each particle its position relative to a reference time and space and, thereby, it is used in this study to analyze the phenomenon evolution and determine the sediment particles diverted into the intake. The comparison between the experimental data and the DPM numerical results shows a good agreement. In order to investigate the mechanism of sediment transport and to evaluate the percentage of the diverted sediments, a parametric study is then conducted through the numerical model, with different positions of the outer bend of the channel, diversion angles of the lateral intake and diversion discharge ratios. The results show that the mechanism of sediment entry into the lateral intake is affected by the diversion discharge ratio. For low discharge ratios, the mechanism of sediment entry to the lateral intake only consists of continuous entrance from the upstream edge of the intake. With the increase of the discharge ratio, it consists of a continuous entrance from the downstream edge and a periodic entrance from the upstream edge of the intake. The DPM results show that, for all diversion discharge ratios, the minimum percentage of sediment entered into the lateral intake corresponds to the position of 120∘ and diversion angle equal to 50∘.

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