A 2D well-balanced, coupled model of water flow, sediment transport, and bed evolution based on unstructured grids with efficient variable storage strategy

2021 ◽  
Vol 36 (1) ◽  
pp. 151-160
Author(s):  
Zhiyuan Yue ◽  
Qingquan Liu ◽  
Wei Huang ◽  
Peng Hu ◽  
Zhixian Cao
Keyword(s):  
Sediment Transport ◽  
Water Flow ◽  
Unstructured Grids ◽  
Coupled Model ◽  
Bed Evolution

scholarly journals A coupled 1-D/2-D model for simulating river sediment transport and bed evolution

2020 ◽  
Vol 22 (5) ◽  
pp. 1122-1137
Author(s):  
Mezbache Salheddine ◽  
Paquier André ◽  
Hasbaia Mahmoud
Keyword(s):  
Sediment Transport ◽  
Flow Direction ◽  
Coupled Model ◽  
Computational Time ◽  
Bed Topography ◽  
Sedimentary Model ◽  
Lateral Coupling ◽  
Morphological Processes ◽  
Bed Evolution ◽  
D Model

Abstract The paper details the method to couple a 1-D hydro-sedimentary model to a 2-D hydro-sedimentary model in order to represent the hydrodynamics and morphological processes during a flood event along a river. Tested on two field cases, the coupled model is stable even in the case of generalized overflow over the riverbanks or of levee breaching. For lateral coupling, the coupled model allows saving computational time compared to a full 2-D model and to provide valuable results concerning the flooding features as well as the evolution of the bed topography. However, despite a similar simplified representation of the sediment features in the 1-D and 2-D models, some discrepancies appear in the case of upstream/downstream coupling along a cross section perpendicular to the flow direction because the assumption of homogeneous velocity and concentration is not valid for estimating sediment transport. Further research is necessary to be able to define a suitable distribution of the sediments on the 1-D side of the boundary between the two models.

scholarly journals Two-dimension coupling model to simulate water flow, sediment transport and bed evolution

2016 ◽  
Vol 48 (6) ◽  
pp. 1537-1553
Author(s):  
Wei Liu ◽  
Siming He ◽  
Qiang Xu
Keyword(s):  
Sediment Transport ◽  
Velocity Profile ◽  
Water Flow ◽  
Morphological Evolution ◽  
Fixed Bed ◽  
Coupling Model ◽  
Momentum Conservation ◽  
Two Dimension ◽  
Bed Evolution ◽  
Flow Mobility

Abstract Catastrophic flood events worldwide have become increasingly more frequent and their dynamics mechanism has attracted much interest as how to predict them by numerical method. As the most common phenomenon occurs in the flowing process, entrainment and deposition can significantly influence flow mobility by increasing in mass and changing in flow character. In this paper, a two-dimension coupling model is presented to simulate water flow, sediment transport and bed evolution based on the shallow water assumption, depth-averaged integration as well as morphological evolution. A new term accounting for the sediment effect on the momentum conservation of water–sediment mixture is added to the model equations by assuming that the flow and the fixed bed is connected by an infinitesimally thin boundary layer, in which the erodible material gains the necessary velocity to enter the flow above. Comparison of numerical results and experimental data indicate the presented model can adequately describe the complex dynamic process, sediment transport and bed evolution. The velocity profile of flow can influence the momentum transfer between the water column and the erodible bottom boundary due to sediment exchange, further influencing flow mobility. Moreover, the velocity profile of flow changes with variations of sediment concentration, bed surface and friction resistance.

scholarly journals An improved coupling model for water flow, sediment transport and bed evolution (CASFE v.1)

2014 ◽  
Vol 7 (2) ◽  
pp. 2429-2454
Author(s):  
S. He ◽  
W. Liu ◽  
X. Li ◽  
C. Ouyang
Keyword(s):  
Sediment Transport ◽  
Water Flow ◽  
Morphological Evolution ◽  
Coupling Model ◽  
Chinese Academy Of Sciences ◽  
Bed Evolution ◽  
The One ◽  
Volume Method ◽  
Academy Of Sciences ◽  
Sediment Mixtures

Abstract. This paper presents a new coupling model to simulate water flow, sediment transport and bed evolution based on the shallow water assumption, depth-average integration as well as the morphological evolution (Chinese Academy of Sciences flow-erosion model, CASFE). The model takes account of the effects of rainfall, entrainment and deposition on the motion of water–sediment mixtures. Limitations and drawbacks of other authors' models are pointed out according to the comparison among these models. The finite volume method has been adopted to solve the one-dimensional dam-break problem considering an erodible bed. Numerical results indicate that the model can adequately describe the complex dynamic problems. Simulation results demonstrate that the entrainment and deposition significantly affects the flow dynamics and morphological evolution.

scholarly journals Sediment Transport and Water Flow Resistance in Alluvial River Channels: Modified Model of Transport of Non-Uniform Grain-Size Sediments

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2038
Author(s):  
Gennady Gladkov ◽  
Michał Habel ◽  
Zygmunt Babiński ◽  
Pakhom Belyakov
Keyword(s):  
Sediment Transport ◽  
Water Flow ◽  
Transport Model ◽  
Flow Characteristics ◽  
Field Measurements ◽  
Field Investigation ◽  
Empirical Modeling ◽  
River Channels ◽  
Channel Deformations ◽  
East European

The paper presents recommendations for using the results obtained in sediment transport simulation and modeling of channel deformations in rivers. This work relates to the issues of empirical modeling of the water flow characteristics in natural riverbeds with a movable bottom (alluvial channels) which are extremely complex. The study shows that in the simulation of sediment transport and calculation of channel deformations in the rivers, it is expedient to use the calculation dependences of Chézy’s coefficient for assessing the roughness of the bottom sediment mixture, or the dependences of the form based on the field investigation data. Three models are most commonly used and based on the original formulas of Meyer-Peter and Müller (1948), Einstein (1950) and van Rijn (1984). This work deals with assessing the hydraulic resistance of the channel and improving the river sediment transport model in a simulation of riverbed transformation on the basis of previous research to verify it based on 296 field measurements on the Central-East European lowland rivers. The performed test calculations show that the modified van Rijn formula gives the best results from all the considered variants.

Bi-directional Coupling of an Unstructured Triangular Meshes-based Integrated Hydrodynamic Model for Heterogeneous Feature-based Urban Flood Simulation

2021 ◽  
Author(s):  
Guoqiang Peng ◽  
Zhuo Zhang ◽  
Tian Zhang ◽  
Zhiyao Song ◽  
Arif Masrur
Keyword(s):  
Water Flow ◽  
Urban Areas ◽  
Overland Flow ◽  
Coupled Model ◽  
Flood Simulation ◽  
Urban Flood ◽  
Essential Condition ◽  
Flow Processes ◽  
Feature Based ◽  
Heterogeneous Feature

Abstract Urban pluvial flash floods have become a matter of widespread concern, as they severely impact people’s lives in urban areas. Hydrological and hydraulic models have been widely used for urban flood management and urban planning. Traditionally, to reduce the complexity of urban flood modelling and simulations, simplification or generalization methods have been used; for example, some models focus on the simulation of overland water flow, and some models focus on the simulation of the water flow in sewer systems. However, the water flow of urban floods includes both overland flow and sewer system flow. The overland flow processes are impacted by many different geographical features in what is an extremely spatially heterogeneous environment. Therefore, this article is based on two widely used models (SWMM and ANUGA) that are coupled to develop a bi-directional method of simulating water flow processes in urban areas. The open source overland flow model uses the unstructured triangular as the spatial discretization scheme. The unstructured triangular-based hydraulic model can be better used to capture the spatial heterogeneity of the urban surfaces. So, the unstructured triangular-based model is an essential condition for heterogeneous feature-based urban flood simulation. The experiments indicate that the proposed coupled model in this article can accurately depict surface waterlogged areas and that the heterogeneous feature-based urban flood model can be used to determine different types of urban flow processes.

Comparison of surface water flow simulation over structured and unstructured grids

2021 ◽  
Author(s):  
Nivedhitha Ajithkumar ◽  
Prabhakar Alok Verma ◽  
Frank B. Osei ◽  
Hari Shankar
Keyword(s):  
Surface Water ◽  
Water Flow ◽  
Unstructured Grids ◽  
Flow Simulation ◽  
Surface Water Flow
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