References of "Dewals, Benjamin"
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See detailAdvanced topics in sediment transport modelling: non-alluvial beds and hyperconcentrated flows
Dewals, Benjamin ULg; Rulot, François ULg; Erpicum, Sébastien ULg et al

in Ginsberg, Silvia Susana (Ed.) Sediment transport (2011)

In this chapter, we first present an original two-phase flow model for the water-sediment mixture, acting as a unified basis for all our subsequent developments. Next, we focus on two topics in which we ... [more ▼]

In this chapter, we first present an original two-phase flow model for the water-sediment mixture, acting as a unified basis for all our subsequent developments. Next, we focus on two topics in which we have made original contributions, namely sediment routing on alluvial and non-alluvial beds and modelling of transient hyperconcentrated flows. In both cases, we use our original two-phase flow modelling framework to derive specific governing equations, for which we discuss their mathematical properties, detail appropriate finite volume numerical scheme and demonstrate their validity through a number of test cases. [less ▲]

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See detailA unified approach for sediment routing over partially non-erodible bottoms and wetting-drying areas
Rulot, François ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Proceedings of the 34th IAHR World Congress (2011)

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See detail2D-Vertical Model for Free Surface Incompressible Flows: Validation and Applications
Detrembleur, Sylvain; Dewals, Benjamin ULg; Pirotton, Michel ULg

in Proc. 34th IAHR World Congress - Balance and Uncertainty (2011)

Efficient design of hydraulic structures such as weirs and bottom outlets requires a detailed description of the complex turbulent flows occurring on these structures. Compared to laboratory experiments ... [more ▼]

Efficient design of hydraulic structures such as weirs and bottom outlets requires a detailed description of the complex turbulent flows occurring on these structures. Compared to laboratory experiments, numerical modeling offers more flexibility and cost-effectiveness to test different designs. The non-hydrostatic 2D-vertical model presented here solves the RANS equations for incompressible flows in the vertical plane. It is based on the projection method for pressure-velocity coupling, while free surface tracking is conducted by means of the level set technique and Sussman’s velocity extension algorithm. It enables to predict accurately the flow pattern in the vertical plane and deals with multiple interfaces (jets, drops…). The solver has been validated for both steady and unsteady free surface flows, based on theoretical and experimental data. The paper will detail the application of the model to a pressurized flow and to a sloshing tank. [less ▲]

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See detailDepth-averaged flowslides model: validation and application to tailings dams and waste dumps failures
Dewals, Benjamin ULg; Archambeau, Pierre ULg; Detrembleur, Sylvain ULg et al

in Chanson, Hubert (Ed.) Proc. of the 34th IAHR World Congress: Balance and Uncertainty: Water in a Changing World (2011)

Flowslides induced by the failure of tailing dams or waste dumps constitute significant industrial hazards. Examples in the past have demonstrated their high potential for casualties and damage ... [more ▼]

Flowslides induced by the failure of tailing dams or waste dumps constitute significant industrial hazards. Examples in the past have demonstrated their high potential for casualties and damage. Geotechnical analyses provide nothing more than the failure criteria. In contrast, once the structure fails, the fluidized material propagates rapidly as a non-Newtonian flow, requiring thus a hydraulic analysis. This paper presents an advanced 2D depth-averaged flow model which accommodates the particular rheology of flowslides, including visco-plasticity and frictional behavior accounting for pore pressure. Based on mass and momentum conservation for the mixture of soil and interstitial fluid, the finite volume model handles flow propagation on dry areas and includes an original treatment of the yield stress in 2D. At a crossroads of geotechnical and hydraulic engineering, the paper depicts the elaboration and validation of a new model readily available for hazard mapping, including extent of affected areas, maximum depths and arrival time. [less ▲]

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See detail1D numerical modeling of the flow over a Piano Key Weir
Erpicum, Sébastien ULg; Machiels, Olivier ULg; Archambeau, Pierre ULg et al

in Erpicum, Sébastien; Laugier, Frédéric; Boillat, Jean Louis (Eds.) et al Labyrinth and Piano Key Weirs - PKW 2011 (2011)

Because of the PK-Weir geometric specificities, its hydraulic capacity remains difficult to predict without using experimental techniques. A 1D numerical model of the flow over a PK-Weir has been ... [more ▼]

Because of the PK-Weir geometric specificities, its hydraulic capacity remains difficult to predict without using experimental techniques. A 1D numerical model of the flow over a PK-Weir has been developed at the Research unit HACH at the University of Liege. It is based on a 1D modeling of the inlet and the outlet separately, with a single upstream reservoir and interactions between both flows by exchange of mass and momentum along the lateral crest. The comparison of the numerical results with various experimental data showed the ability of the numerical model to predict with reasonable accuracy the release capacity of a PK-Weir, whatever its geometry. The tests of the solver enable to highlight the significant influence of the inlet and outlet width on the weir release capacity. They also suggest that improvements of the numerical model may lie in the evaluation of the discharge coefficient of the lateral crest. [less ▲]

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See detailInfluence of the alveoli slopes on the discharge capacity of Piano Key Weirs
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Proceedings of the 34th IAHR world congress (2011)

Piano Key Weir is a cost effective solution for rehabilitation as well as for new dam project with a high level of constraints (space, flood discharge, reservoir level).If the efficiency of the Piano Key ... [more ▼]

Piano Key Weir is a cost effective solution for rehabilitation as well as for new dam project with a high level of constraints (space, flood discharge, reservoir level).If the efficiency of the Piano Key Weir has already been well demonstrated, the definition of its optimal geometry has been still poorly approached. In order to improve the design of the complex geometry of this structure, the study of the influence of the mean geometrical parameters on the discharge capacity is an essential stage. Following a former experimental study of the flow over Piano Key Weirs, highlighting the mean influence of three geometrical parameters, this paper presents the results of an experimental parametric study. These results highlight the influence of the alveoli bottom slopes on the Piano Key Weir release capacity. Comparisons with numerical and analytical results, as well as design advices are also provided. [less ▲]

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See detailVarying the alveoli slopes of Piano key Weirs: Interests and limitations
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Pina, C.; Portela, E.; Gomes, J. (Eds.) Proceedings of the 6th International conference on dam engineering (2011)

Piano Key Weir is a cost effective solution for rehabilitation as well as for new dam project with a high level of constraints (space, flood discharge, reservoir level). Its labyrinth shape permits the ... [more ▼]

Piano Key Weir is a cost effective solution for rehabilitation as well as for new dam project with a high level of constraints (space, flood discharge, reservoir level). Its labyrinth shape permits the evacuation of discharges till four times more important than ogee-crested weirs with the same length at the dam crest, when the use of overhangs permits the building of the auto-equilibrated structure directly on dam crest. If the efficiency of the Piano Key Weir has already been well demonstrated, the definition of its optimal geometry has been still poorly approached. In order to improve the design of the complex geometry of this structure, the study of the influence of the mean geometrical parameters on the discharge capacity is an essential stage. Following a former experimental study of the flow over Piano Key Weirs, highlighting the mean influence of three geometrical parameters, this paper presents the results of an experimental parametric study. These results highlight the influence of the alveoli bottom slopes on the Piano Key Weir release capacity. In this paper, the interests and limitations of the variation of the slopes are explained. Recommendations directly linked to the observation of the experimental models are also provided to improve the design of PKW. [less ▲]

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See detailAn exact Riemann Solver and Godunov Scheme for Simulating Highly Transient Mixed Flows
Kerger, François ULg; Archambeau, Pierre ULg; Erpicum, Sébastien ULg et al

in Journal of Computational & Applied Mathematics (2011), 235

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See detailCaractérisation micro-échelle du risque d’inondation : modélisation hydraulique détaillée et quantification des impacts socio-économiques
Dewals, Benjamin ULg; Detrembleur, Sylvain ULg; Archambeau, Pierre ULg et al

in Houille Blanche (2011), (2), 28-34

The paper presents a consistent micro-scale flood risk analysis procedure, relying on detailed 2D inundation modelling as well as on high resolution topographic and land use database. The flow model is ... [more ▼]

The paper presents a consistent micro-scale flood risk analysis procedure, relying on detailed 2D inundation modelling as well as on high resolution topographic and land use database. The flow model is based on the shallow-water equations, solved by means of a finite volume scheme on multiblock structured grids. Using highly accurate laser altimetry, the simulations are performed with a typical grid spacing of 2m, which is fine enough to represent the flow at the scale of individual buildings. The methodology is first described, both in terms of hydraulic modelling and evaluation of people and assets vulnerability. The analysis scale of the procedure enables its development following an object-oriented approach. Finally, the applicability of the procedure is demonstrated through a case study for which three different protection measures are evaluated. Detailed analysis of these measures highlights significantly different influences from those measures on the risk curves. [less ▲]

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See detailFailure of dams arranged in series or in complex
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Detrembleur, Sylvain ULg et al

in Natural Hazards (2011), 56(3), 917-939

A practical methodology has been developed for predicting flows generated by dam failures or malfunctions in a complex or a series of dams. A twofold approach is followed. First, the waves induced in the ... [more ▼]

A practical methodology has been developed for predicting flows generated by dam failures or malfunctions in a complex or a series of dams. A twofold approach is followed. First, the waves induced in the downstream reservoirs are computed, as well as hydrodynamic impacts induced on downstream dams and dikes are estimated. Second, the flood wave propagation and the inundation process are simulated in the downstream valley, accounting for possible dam collapse or breaching in cascade. Two complementary flow models are combined: a two-dimensional fully dynamic model and a simplified lumped model. At each stage, the methodology provides guidelines to select the most appropriate model for efficiently computing the induced flows. Both models handle parametric modeling of gradual dam breaching. The procedure also incorporates prediction of breach formation time and final width, as well as sensitivity analysis to compensate for the high uncertainties remaining in the estimation of breach parameters. The applicability of the modeling procedure is demonstrated for a case study involving a 70m-high gravity concrete dam located upstream of four other dams. [less ▲]

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See detailEnergy dissipation on a stepped spillway downstream of a Piano Key Weir - Experimental study
Erpicum, Sébastien ULg; Daux, Christophe; Machiels, Olivier ULg et al

in Erpicum, Sébastien; Laugier, Frederic; Boillat, Jean Louis (Eds.) et al Labyrinth and Piano Key Weirs - PKW 2011 (2011)

Piano Key Weir (PKW) is a new type of weir showing appealing hydraulic capacities. Its specific geometric features create different interacting flows and jets downstream of the structure. This suggests ... [more ▼]

Piano Key Weir (PKW) is a new type of weir showing appealing hydraulic capacities. Its specific geometric features create different interacting flows and jets downstream of the structure. This suggests that the use of a PKW to control the flow upstream of a stepped spillway may help in enhancing energy dissipation on the downstream channel. The first results of an experimental study carried out at the Laboratory of Engineering Hydraulics – HACH in the scope of a Coyne & Bellier – Tractebel Engineering project are presented in the paper. The goal of the study was to compare the energy dissipation on a stepped spillway downstream of a PKW with the one which takes place on the same spillway equipped with a standard ogee-crested weir. Despite similar global energy dissipation rates whatever the weir type due to the relative important height of the spillway, significant differences in the aeration of the flow along the spillway have been shown. This paves the way to further investigations. [less ▲]

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See detailPiano Key Weir preliminary design method – Application to a new dam project
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Erpicum, Sébastien; Laugier, Frederic; Boillat, Jean Louis (Eds.) et al Labyrinth and Piano Key Weirs - PKW 2011 (2011)

Within the framework of development of PKW use for rehabilitation as well as for new dam projects, the development of efficient design methods is essential. Currently, the design of PKW projects is done ... [more ▼]

Within the framework of development of PKW use for rehabilitation as well as for new dam projects, the development of efficient design methods is essential. Currently, the design of PKW projects is done by mean of scale modeling, on the basis of a geometry initially designed based on the general knowledge issued from idealized experimental studies and former PKW buildings. This paper presents a systematic method for PKW preliminary design. The method is based on extrapolation of existing experimental results to develop one or several available project designs, regarding the project constraints (discharge, reservoir levels, available space, …). The model permits then the optimization of the design depending on technical and economical interests (increase of the safety, decrease of the maximal head, limiting the weir dimensions, limiting construction costs, …). The application of the method to a new large dam project is presented, highlighting the interest of the method for the optimization of the design depending on technical and economical interests. [less ▲]

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See detailInfluence of the PKW height on its discharge capacity
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Erpicum, Sébastien; Laugier, Frédéric; Boillat, Jean Louis (Eds.) et al Labyrinth and Piano Key Weirs - PKW 2011 (2011)

Within the framework of Piano Key Weir (PKW) development, the hydraulic optimization of its geometry seems essential. First systematic studies of all the geometrical parameters of the PKW highlight a more ... [more ▼]

Within the framework of Piano Key Weir (PKW) development, the hydraulic optimization of its geometry seems essential. First systematic studies of all the geometrical parameters of the PKW highlight a more important influence of some parameters compared to other ones. A former study led, at the University of Liege, on a large scale model of PKW highlights the main influence of the inlet cross section on the global discharge capacity of the weir. Based on this finding, the geometrical parameters influencing the inlet cross section seem to be the most influential parameters of the weir efficiency. This paper presents results of an experimental study using models of PKW with varying height. The mean non-dimensional parameters characterizing the geometry of the models are maintained constant, only varying the slope of the alveoli. The results of the 7 models studied, with a wide range of slopes (height over length) from 0.25 to 1.5, are presented. Based on these results, an analytical formulation of the unit discharge over a PKW as a function of its height is developed. [less ▲]

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See detailEfficient hydraulic numerical modeling with multiblock grids and linked models
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Houille Blanche (2011), 3

In the field of numerical hydraulic engineering, the size of the simulations is one of the current challenges to consider with sufficient precision the large areas involved by practical applications. In ... [more ▼]

In the field of numerical hydraulic engineering, the size of the simulations is one of the current challenges to consider with sufficient precision the large areas involved by practical applications. In this scope, the linking in the same computational domain of different solvers, each one used in the part of the simulation where its characteristics are most suitable, opens the door to huge modeling possibilities. Such optimized hydraulic numerical modeling is presented in this paper with a multiblock multimodel 2D solver and its linking to a 1D model. After a description of the solvers, with emphasis on the linking procedures, theoretical test cases and real applications are presented. [less ▲]

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See detailWOLF 1D PKW - 1D numerical model of the flow over a piano key weir
Erpicum, Sébastien ULg; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

Software (2011)

The Piano Key Weir (PKW) is a new type of free weir, similar to a labyrinth weir, showing appealing performance to release high discharges under limited head levels in the upstream reservoir. Because of ... [more ▼]

The Piano Key Weir (PKW) is a new type of free weir, similar to a labyrinth weir, showing appealing performance to release high discharges under limited head levels in the upstream reservoir. Because of the PKW geometric specificities, its hydraulic capacity remains difficult to predict without using experimental techniques. Wolf1D PKW numerical model has been developed at the Research Unit HACH at the University of Liege to model the flow over a PKW. It is based on a 1D modelling of the PKW main elements separately (the inlet and the outlet), with a single upstream reservoir and interactions between both flows by exchange of mass and momentum along the lateral crest. [less ▲]

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See detailOn the Assessment of a Modified Diffusion-Wave Approximation Model in the Framework of Overland Flow
Paulus, Raphaël ULg; Archambeau, Pierre ULg; Erpicum, Sébastien ULg et al

in Chanson, Hubert (Ed.) Balance and Uncertainty: Water in a Changing World (2011)

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See detailHandling of the 3D Behaviour of the Unsaturated Layer using a Vertical 1D Model for the Richards Equation along with Diffusive Horizontal Fluxes
Paulus, Raphaël ULg; Archambeau, Pierre ULg; Erpicum, Sébastien ULg et al

in Chanson, Hubert (Ed.) Balance and Uncertainty: Water in a Changing World (2011)

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See detailIncorporating climate change scenarios into new operating rules for large reservoirs: a transnational assessment in the Meuse basin
Dewals, Benjamin ULg; Detrembleur, Sylvain ULg; Archambeau, Pierre ULg et al

in Schleiss, Anton (Ed.) Dams and Reservoirs under changing Challenges (2011)

Opportunities for updating and optimizing current operating rules are being evaluated for the Vesdre reservoirs in Belgium (50 M m³) and the Rur complex in Germany (300 M m³). This assessment is conducted ... [more ▼]

Opportunities for updating and optimizing current operating rules are being evaluated for the Vesdre reservoirs in Belgium (50 M m³) and the Rur complex in Germany (300 M m³). This assessment is conducted transnationally at the scale of the Meuse river basin. Common methodological approaches are followed in both countries and operating rules are analyzed in light of common climate change scenarios, recently defined for the whole Meuse basin. Similar risk-based approaches are used consistently in both countries to evaluate the performance of new operating rules in terms of risk reduction for floods and low flows. [less ▲]

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See detailImpact of Climate change on inundation hazard along river Meuse
Dewals, Benjamin ULg; Detrembleur, Sylvain ULg; Archambeau, Pierre ULg et al

Conference (2010, December 16)

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