Understanding Morphodynamic Changes of a Tidal River Confluence through Field Measurements and Numerical Modeling

Xie, Qiancheng; Yang, James; Lundström, T. Staffan; Dai, Wujiao

doi:10.3390/w10101424

Cited by 18 publications

(16 citation statements)

References 43 publications

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“…In contrast, most 3D numerical models (e.g., Delft3D, Fluent, RSim-3D, SSIIM) solving the fully three-dimensional Reynolds-equations with different turbulence closures, typically permit the application of the equivalent sand roughness k s [51], which is based on the sediment size and also allows accounting for the average height of bed forms. To date, numerous studies [52][53][54][55][56][57][58][59][60][61] have been published based on the mentioned numerical models to calculate hydrodynamic properties and their impacts on rivers.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Hydrodynamics Simulated by 1D, 2D and 3D Models Focusing on Bed Shear Stresses

Glock

Tritthart

Habersack

et al. 2019

Water

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For centuries, scientists have been attempting to map complex hydraulic processes to empirical formulas using different flow resistance definitions, which are further applied in numerical models. Now questions arise as to how consistent the simulated results are between the model dimensions and what influence different morphologies and flow conditions have. For this reason, 1D, 2D and 3D simulations were performed and compared with each other in three study areas with up to three different discharges. A standardized, relative comparison of the models shows that after successful calibration at measured water levels, the associated 2D/1D and 3D/1D ratios are almost unity, while bed shear stresses in the 3D models are only about 62–86% of the simulated 1D values and 90–100% in the case of 2D/1D. Reasons for this can be found in different roughness definitions, in simplified geometries, in different calculation approaches, as well as in influences of the turbulence closure. Moreover, decreasing 3D/1D ratios of shear stresses were found with increasing discharges and with increasing slopes, while the equivalent 2D/1D ratios remain almost unchanged. The findings of this study should be taken into account, particularly in subsequent sediment transport simulations, as these calculations are often based on shear stresses.

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Section: Introductionmentioning

confidence: 99%

Comparison of Hydrodynamics Simulated by 1D, 2D and 3D Models Focusing on Bed Shear Stresses

Glock

Tritthart

Habersack

et al. 2019

Water

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“…Bolla Pittaluga et al [13] worked on the morphological equilibrium of many tidal configurations using a 1D model. Xie, et al [14] examined the morpho-dynamics of a tidal confluence through field investigations and numerical simulations. Zhou, et al [15] reviewed the concept of equilibrium and suggested that it can only be found in ideal situations of numerical or physical models.…”

Section: Items Non-tidal Confluence Tide-driven Confluencementioning

confidence: 99%

Flow, Sediment, and Morpho-Dynamics of River Confluence in Tidal and Non-Tidal Environments

Bilal

Xie

Zhai

2020

JMSE

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River confluences are the key features of the drainage basins, as their hydrological, geomorphological, and ecological nature strongly influences the downstream river characteristics. The river reaches near the coastal zones, which also makes them under the influence of tidal currents in addition to their runoff. This causes a bi-directional flow and makes the study of confluences more interesting and complex in these areas. There is a reciprocal adjustment of flow, sediment, and morphology at a confluence, and its behaviors, differ greatly in tidal and non-tidal environments. Existing studies of the river junctions provide a good account of information about the hydrodynamics and bed morphology of the confluent areas, especially the unidirectional ones. The main factors which affect the flow field include the angle of confluence, flow-related ratios (velocity, discharge, and momentum) of the merging streams, and bed discordance. Hydraulically, six notable zones are identified for unidirectional confluences. However, for bi-directional (tidal) junctions, hydrodynamic zones always remain in transition but repeat in a cycle and make four different arrangements of flow features. This study discusses the hydrodynamics, sediment transport, morphological changes, and the factors affecting these processes and reviews the recent research about the confluences for these issues. All of these studies provide insights into the morpho-dynamics in tidal and non-tidal confluent areas.

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“…recently published results such as Xie, Yang, Lundström, and Dai (2018) and Xie, Yang, and Lundström (2019).…”

Section: Mathematical Formulationmentioning

confidence: 99%

Flow and sediment behaviours and morpho‐dynamics of a diffluence−Confluence unit

Xie

Yang

Lundström

2020

River Research & Apps

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A diffluence-confluence unit is an elementary component within a river system and presents a complex yet linked pattern of both flow and sediment transport in between. This study deals, by means of field investigations and numerical modelling, with morpho-dynamics of such a unit on the lower Yangtze River reaches. The unit comprises, looking downstream, a secondary (left) course and a main (right) course. Field surveys are performed for measurements of flow discharge, sediment loads at selected locations and river bathymetry at certain intervals. The field data show that

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Understanding Morphodynamic Changes of a Tidal River Confluence through Field Measurements and Numerical Modeling

Cited by 18 publications

References 43 publications

Comparison of Hydrodynamics Simulated by 1D, 2D and 3D Models Focusing on Bed Shear Stresses

Comparison of Hydrodynamics Simulated by 1D, 2D and 3D Models Focusing on Bed Shear Stresses

Flow, Sediment, and Morpho-Dynamics of River Confluence in Tidal and Non-Tidal Environments

Flow and sediment behaviours and morpho‐dynamics of a diffluence−Confluence unit

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