Three-dimensional (3D) modeling of non-uniform sediment transport in a channel bend with unsteady flow

Fischer-Antze, Tim; Rüther, Nils; Olsen, Nils; Gutknecht, Dieter

doi:10.3826/jhr.2009.3252

Cited by 34 publications

(16 citation statements)

References 12 publications

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“…In largescale fluvial simulations a minimum number of vertical layers required to cover the three-dimensionality of the flow is reported in literature, e.g. five (Fischer-Antze, Olsen, & Gutknecht, 2008;Fischer-Antze, Rüther, Olsen, & Gutknecht, 2009) to eight layers as reported by Tritthart et al (2011). However, when the model is applied to smaller scales, due to the lack of proper near-wall treatment algorithms and refinement, the results tend to diverge from the measured values.…”

Section: Discussionmentioning

confidence: 80%

Accuracy and comparison of standard k-ϵ with two variants of k-ω turbulence models in fluvial applications

Farhadi

Mayrhofer

Tritthart

et al. 2017

Engineering Applications of Computational Fluid Mechanics

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Racetrack flumes are established experimental settings in ecohydraulics and sediment studies. Their experimental results are often coupled with numerical simulations. The two-equation turbulence closures of the Reynolds-Averaged Navier-Stokes equations are applied widely in such engineering applications. They are preferred for their ease of use and low computational costs compared with more sophisticated turbulence models involving large-scale fluvial simulations. Here, three variants of two-equation models, i.e. the standard k-ε model and two variants of k-ω models, were applied to tackle mean flow and turbulence in a racetrack flume and a river reach. Regarding model performances, we found an overall reasonable agreement between simulated and measured mean velocity values. Nonetheless, the simulated turbulent kinetic energy exhibited discrepancies to the measured values. The computational costs of all investigated model variants are comparable. Therefore, there is no significant preference among models. The findings confirm the application of these model approaches for mean flow-related investigations (e.g. habitat modeling) but suggest exercising caution for applications sensitive to turbulent processes. ARTICLE HISTORY

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Section: Discussionmentioning

confidence: 80%

Accuracy and comparison of standard k-ϵ with two variants of k-ω turbulence models in fluvial applications

Farhadi

Mayrhofer

Tritthart

et al. 2017

Engineering Applications of Computational Fluid Mechanics

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“…Nevertheless, the numerical simulation of morphodynamic processes can contribute to the better performance of river engineering activities, e.g., when planning restoration measures, and it is considered a widely applied investigation tool with many benefits. However, the reliable numerical description of the interaction between river hydrodynamics and the morphological features is a challenging task in rivers with uniform bed material composition, but shows even higher difficulties in the case of mixed-size bed material conditions (e.g., [25][26][27][28][29]). When the grain sizes cover a smaller range in the bed material, the potential erosion results also in a quite uniform grain size range of the bed load transport.…”

Section: Problem Statementmentioning

confidence: 99%

A Shear Reynolds Number-Based Classification Method of the Nonuniform Bed Load Transport

Török

Józsa

Baranya

2019

Water

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The aim of this study is to introduce a novel method which can separate sand- or gravel-dominated bed load transport in rivers with mixed-size bed material. When dealing with large rivers with complex hydrodynamics and morphodynamics, the bed load transport modes can indicate strong variation even locally, which requires a suitable approach to estimate the locally unique behavior of the sediment transport. However, the literature offers only few studies regarding this issue, and they are concerned with uniform bed load. In order to partly fill this gap, we suggest here a decision criteria which utilizes the shear Reynolds number. The method was verified with data from field and laboratory measurements, both performed at nonuniform bed material compositions. The comparative assessment of the results show that the shear Reynolds number-based method operates more reliably than the Shields–Parker diagram and it is expected to predict the sand or gravel transport domination with a <5% uncertainty. The results contribute to the improvement of numerical sediment transport modeling as well as to the field implementation of bed load transport measurements.

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“…The length of the recirculation zone is then the main testing parameter. A collapsing water column or a wave can be used for testing free surface algorithms Simplified cases do not always have to involve a simplified geometry [3].…”

Section: Testing For Simplified Situationsmentioning

confidence: 99%

Evaluating Methods for 3D CFD Models in Sediment Transport Computations

Madihi

Amerian

2015

AJCE

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Usual uncertainties in computational fluid dynamics (CFD) results include numerical errors, modeling errors, program bugs, mistakes in input parameters and boundary conditions. The errors can be assessed using itemized results from the CFD program together with its documentation. Each uncertainty can be assessed by evaluating the variables against each other, parameter responsiveness examinations and testing for simplified items. The role is made easier if the program is as transparent as possible. This means that the user can see the values of all the pertinent variables and mediatory results for the whole computational domain. Together with an extensive collection of documents of the computer program that includes all the formulas used, the user can be able to find the causes of suspect results, including an estimation of possible bugs. An important tool in the testing of a CFD program is using simplified cases, generally channels with uniform one-dimensional flow.

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Three-dimensional (3D) modeling of non-uniform sediment transport in a channel bend with unsteady flow

Cited by 34 publications

References 12 publications

Accuracy and comparison of standard k-ϵ with two variants of k-ω turbulence models in fluvial applications

Accuracy and comparison of standard k-ϵ with two variants of k-ω turbulence models in fluvial applications

A Shear Reynolds Number-Based Classification Method of the Nonuniform Bed Load Transport

Evaluating Methods for 3D CFD Models in Sediment Transport Computations

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