Depth-Averaged Two-Dimensional Model of Unsteady Flow and Sediment Transport due to Noncohesive Embankment Break/Breaching

Wu, Weiming; Marsooli, Reza; He, Zhiguo

doi:10.1061/(asce)hy.1943-7900.0000546

Cited by 78 publications

(64 citation statements)

References 2 publications

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“…Figure 8 shows the computed and measured stage hydrographs at the eight gauges. The computed stage hydrographs at gauges 1 and 4 are about 3.0 cm lower than the measured ones on average (Figure 8(a)), which is similar to that due to Wu et al [33]. One of the possible reasons for the discrepancy is that these two gauges are located at the suddenly expanded corner where the flow is highly three-dimensional and may not be fully represented by shallow water hydrodynamic models.…”

Section: Dam Break Flow Over Mobile Bedsupporting

confidence: 78%

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Coupled flood and sediment transport modelling with adaptive mesh refinement

Huang

Cao

Pender

et al. 2015

Sci. China Technol. Sci.

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Coupled flood and sediment transport modelling in large-scale domains has for long been hindered by the high computational cost. Adaptive mesh refinement is one of the viable ways to solving this problem without degrading the accuracy. This goal can be accomplished through mesh adaptation, e.g., mesh coarsening and refining based on the dynamic regime of the flow and sediment transport along with bed evolution. However, previous studies in this regard have been limited to cases either without involving sediment transport or featuring flow-sediment-bed decoupling and the assumption of sediment transport capacity, which are not generally justified. Here, a coupled hydrodynamic and non-capacity sediment transport model is developed on adaptive non-uniform rectangular mesh. The proposed model is validated against experimental tests and numerical results based on the fixed meshes. It is demonstrated that the proposed model can properly capture shock waves, resolve the wetting/drying transition and reproduce morphological evolution. Compared with models based on the fixed meshes, the proposed model features great advantage in computational efficiency and holds promise for wide applications.shallow water flow, sediment transport, adaptive mesh Citation:Huang W, Cao Z X, Pender G, et al. Coupled flood and sediment transport modelling with adaptive mesh refinement.

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Section: Dam Break Flow Over Mobile Bedsupporting

confidence: 78%

“…The experiment involved both initially wet and dry bed scenarios downstream of the gate. Here, only the initially dry case was selected, which was thought to be most difficult case to model [33]. Ultrasonic probes were used to measure the water level at eight gauge points ( Figure 7).…”

Section: Dam Break Flow Over Mobile Bedmentioning

confidence: 99%

Coupled flood and sediment transport modelling with adaptive mesh refinement

Huang

Cao

Pender

et al. 2015

Sci. China Technol. Sci.

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“…The flood wave caused by a dam breach is usually a progressive flow-sediment interaction event, not a sudden collapse (Guan et al, 2014;Pickert et al, 2011;Wu et al, 2012). A small-scale experimental event was tested in this section in order to emphasise the blockage effects of sediment material on flow propagation.…”

Section: Partial Dam Breach Vs Sudden Dam Breachmentioning

confidence: 99%

Multiple effects of sediment transport and geomorphic processes within flood events: Modelling and understanding

Guan

Wright

Sleigh

2015

International Journal of Sediment Research

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Flood events can induce considerable sediment transport which in turn influences flow dynamics. This study investigates the multiple effects of sediment transport in floods through modelling a series of hydraulic scenarios, including small-scale experimental cases and a full-scale glacial outburst flood. A non-uniform, layer-based morphodynamic model is presented which is composed of a combination of three modules: a hydrodynamic model governed by the two-dimensional shallow water equations involving sediment effects; a sediment transport model controlling the mass conservation of sediment; and a bed deformation model for updating the bed elevation. The model is solved by a second-order Godunov-type numerical scheme. Through the modelling of the selected sediment-laden flow events, the interactions of flow and sediment transport and geomorphic processes within flood events are elucidated. It is found that the inclusion of sediment transport increases peak flow discharge, water level and water depth in dam-break flows over a flat bed. For a partial dam breach, sediment material has a blockage effect on the flood dynamics. In comparison with the 'sudden collapse' of a dam, a gradual dam breach significantly delays the arrival time of peak flow, and the flow hydrograph is changed similarly. Considerable bed erosion and deposition occur within the rapid outburst flood, which scours the river channel severely. It is noted that the flood propagation is accelerated after the incorporation of sediment transport, and the water level in most areas of the channel is reduced.

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“…The models by Fread [1988], Walder and O'Connor [1997], Macchione [2008], and Hou [2009] solve ordinary differential equations (ODEs) in time. More complex models solving partial differential equations have also been proposed [Tingsanchali and Chinnarasri, 2001;Liu et al, 2012;Wu et al, 2012]. So far, however, models of this type have required numerical solutions implemented as computer codes.…”

Section: Introductionmentioning

confidence: 99%

Analytical solutions for gradual dam breaching and downstream river flooding

Capart

2013

Water Resources Research

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[1] An analytical model is proposed to describe lake drainage and downstream flooding due to the gradual breaching of natural and manmade earthen dams. Erodible triangular dams are considered, undergoing gradual incision by a breaching channel of constant effective width. Adopting a simple stream power law for dam material transport, the long profile evolution of the breaching channel is governed by a diffusion equation with variable diffusion rate, proportional to the water discharge. The resulting flood is routed downstream using the kinematic wave equation. Moving boundary problems are obtained due to retrogression of the breach crest, and to the downstream propagation of the flood wavefront. For both the dam breaching and flood routing problems, explicit analytical solutions are derived. They depict a breaching process that is at first self-accelerating, then becomes self-limiting. Results include boundary paths, long profiles, and stage and discharge hydrographs. In particular, the breaching solution yields a discharge hydrograph of simple analytical shape that turns out to be ideally suited for kinematic wave routing. The model is applied to the well-documented breaching of the Tangjiashan landslide dam, Sichuan, in June 2008. Calculated results for this and other cases are in reasonably good agreement with the measured data. As the model is simple to apply, with minimal computational and data requirements, it could prove useful as a tool for rapid risk assessment. The proposed analytical approach also complements numerical models by providing more transparent links between solution outcomes and the problem data.

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Depth-Averaged Two-Dimensional Model of Unsteady Flow and Sediment Transport due to Noncohesive Embankment Break/Breaching

Cited by 78 publications

References 2 publications

Coupled flood and sediment transport modelling with adaptive mesh refinement

Coupled flood and sediment transport modelling with adaptive mesh refinement

Multiple effects of sediment transport and geomorphic processes within flood events: Modelling and understanding

Analytical solutions for gradual dam breaching and downstream river flooding

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