References of "Dewals, Benjamin"
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See detailHydraulic behavior of Piano Key Weirs: experimental approach
Machiels, Olivier ULiege; Erpicum, Sébastien ULiege; Archambeau, Pierre ULiege et al

in Janssen, Robert; Chanson, Hubert (Eds.) 3rd Int. Junior Researcher and Engineer Worjshop on Hydraulic Structures (2010, May)

The Piano Key Weir (PKW) is a particular geometry of weir similar to a labyrinth shape that features overhanging cycle ends to reduce the base length. Together with its high discharge capacity for low ... [more ▼]

The Piano Key Weir (PKW) is a particular geometry of weir similar to a labyrinth shape that features overhanging cycle ends to reduce the base length. Together with its high discharge capacity for low heads, this geometric feature makes the PKW an interesting solution for dam rehabilitation, permitting the placement of the weir directly on dam crest. However, PKW stays a new type of weir, firstly designed in 2001 and built for the first time in 2006 by Electricité de France (EDF). Even if the first experimental studies confirmed its discharge capacities, lacks persist in the understanding of the flow behaviour upstream, along and downstream of this complex structure. This paper presents the mean results and observations obtained from experiments on a large scale model of PKW. The hydraulics of the structure is clarified based on measurements of water depths, pressures, velocities and discharges on each part of the weir. These observations explain the effect of geometric improvements proposed in former studies. [less ▲]

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See detailFlood Protection Design Based on Micro-scale Risk Modelling
Ernst, Julien ULiege; Dewals, Benjamin ULiege; Detrembleur, Sylvain ULiege et al

Poster (2010, April 22)

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See detailCaractérisation micro-échelle du risque d’inondation : modélisation hydraulique détaillée et impacts socio-économiques
Ernst, Julien ULiege; Dewals, Benjamin ULiege; Detrembleur, Sylvain ULiege et al

in Risque d'Inondation en Ile de France, 100 ans après les crues de 1910 (2010, March)

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See detailMulti-scale modelling of sediment transport
Dewals, Benjamin ULiege

Conference (2010, January 07)

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See detailClassification of flow patterns in rectangular shallow reservoirs
Dufresne, Matthieu; Dewals, Benjamin ULiege; Erpicum, Sébastien ULiege et al

in Journal of Hydraulic Research (2010), 48(2), 197-204

This work focuses on the experimental classification of flow patterns in rectangular shallow reservoirs, including symmetric flows without any reattachment point to asymmetric flows with one reattachment ... [more ▼]

This work focuses on the experimental classification of flow patterns in rectangular shallow reservoirs, including symmetric flows without any reattachment point to asymmetric flows with one reattachment point, two reattachment points, or two reattachment points and one detachment point. The median position and the natural variability of the reattachment lengths of asymmetric flows were measured for forty geometric and hydraulic conditions. The effects of dimensionless flow depth, Froude number, lateral expansion ratio and dimensionless length on the median reattachment lengths were analyzed. A number of regression equations were proposed. For “high” dimensionless flow depths and a Froude number of 0.20, a shape parameter was proposed for predicting the transition between symmetric and asymmetric flows. The results of this study are useful knowledge for improving current methods to predict the trapping efficiency and the preferential regions of deposition in reservoirs. [less ▲]

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See detailAnalyse expérimentale de l'influence des largeurs d'alvéoles sur la débitance des déversoirs en touches de piano
Machiels, Olivier ULiege; Erpicum, Sébastien ULiege; Archambeau, Pierre ULiege et al

in Houille Blanche (2010), (2), 22-28

Within the framework of updating the release and storage capacities of existing reservoirs, the use of piano keys weirs (PKW) can be an interesting alternative either to increase the discharge of a free ... [more ▼]

Within the framework of updating the release and storage capacities of existing reservoirs, the use of piano keys weirs (PKW) can be an interesting alternative either to increase the discharge of a free weir without changing the weir layout or the reservoir level, or increase the reservoir level before discharge while keeping the weir layout and the level of safety. In order to help to the understanding of the behavior of this new type of weirs and to characterize their hydraulic potential, the results of an experimental study with for objectives to study the influence of the relative width of the inlets and outlets on the hydrodynamic characteristics of the structure are presented. A process oriented analytical formulation for the evaluation of the discharge coefficient of the PKW tested on scale models is proposed. It is in satisfactory agreement with the experimental results and leads to an objective evaluation of the optimal ratio of the alveoli widths. [less ▲]

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See detailContribution to the study of piano Key Weir hydraulics
Erpicum, Sébastien ULiege; Machiels, Olivier ULiege; Dewals, Benjamin ULiege et al

in Proceedings of the 8th ICOLD European Club Symposium (2010)

Within the framework of updating the release and storage capacities of existing reservoirs, the use of piano key weirs (PKW) can be an interesting alternative either to increase the discharge of a free ... [more ▼]

Within the framework of updating the release and storage capacities of existing reservoirs, the use of piano key weirs (PKW) can be an interesting alternative either to increase the discharge of a free weir without changing the weir width on the dam crest nor the reservoir level, or to increase the threshold reservoir level before releasing water while keeping the weir width and the level of safety. Results of first experiments on scale models have shown the high efficiency of PKW in terms of discharge capacity. But, even if PKW projects start to be developed on real structures, lacks persist in the understanding of the flow behavior on this new type of weir, in the characterization of their hydraulic potential and in the availability of design guidelines. This paper presents the results of several research projects, based on both numerical and physical modeling, carried out on this topic at the Laboratory of Engineering Hydraulics of the University of Liege. The researches rely on physical experiments on scale models of idealized PKW elements or real structures, as well as on numerical modeling with specifically developed solvers. The paper presents an overview of these projects, emphasizing the most important results regarding PKW design and performance. [less ▲]

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See detailHybrid modelling of dike-break induced flows
Roger, Sebastian; Dewals, Benjamin ULiege; Erpicum, Sébastien ULiege et al

in Dittrich, Andreas; Koll, Katinka; Aberle, Jochen (Eds.) et al River Flow 2010 (2010)

In a hybrid approach experimental model data are combined with results from 3D and 2D numerical modelling. The latter was conducted by two different models solving the depth-averaged shallow water ... [more ▼]

In a hybrid approach experimental model data are combined with results from 3D and 2D numerical modelling. The latter was conducted by two different models solving the depth-averaged shallow water equations. 3D computations are based on the REYNOLDS-averaged NAVIER-STOKES equations (RANS) using a volume of fluid approach to capture the free water surface. Measurements were performed on a scale model which was especially designed to reproduce the specific conditions of dike breaks. In various simulations it turned out that 2D shallow water models are able to reproduce steadystate flow patterns of dike-break induced flows and that there is a low sensitivity of the solution concerning turbulence modelling, bed and wall roughness. Nevertheless, final flow splits and breach discharges are systematically underestimated. This discrepancy seems to result from inherent modelling assumptions such as zero-vertical velocity and hydrostatic pressure distribution. Therefore, the complementary use of 3D RANS and 2D depth-averaged modelling frameworks for detailed predictions of dike-break induced flows is discussed in the present paper, based on BOUSSINESQ and pressure coefficients, which represent effects of non-uniform velocity profiles and non-hydrostatic pressure distribution over water depth, respectively. Values of these coefficients are inferred from 3D numerical results for the final steady state. [less ▲]

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See detail1D numerical approach to model the flow over a piano key weir (PKW)
Erpicum, Sébastien ULiege; Machiels, Olivier ULiege; Archambeau, Pierre ULiege et al

in Proc. Int. Conf. SimHydro 2010: Hydraulic modeling and uncertainty (2010)

Piano Key Weir (PKW) is a new type of weir showing appealing hydraulic capacities, in particular for low heads. However, its complex geometry, with a large set of parameters, makes difficult the ... [more ▼]

Piano Key Weir (PKW) is a new type of weir showing appealing hydraulic capacities, in particular for low heads. However, its complex geometry, with a large set of parameters, makes difficult the understanding of the flow features and consequently the definition of an optimal design. In this paper, we investigate how a 1D numerical approach can predict the flow over a PKW and thus help in identifying the most relevant geometric parameters. After a detailed description of the numerical model, a comparison of the numerical results with experimental data is realized, showing promising results. [less ▲]

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See detailModelling Free-surface Flows and Highly Transient Mixed Flows: A 1D Three-phase Approach
Kerger, François ULiege; Archambeau, Pierre ULiege; Dewals, Benjamin ULiege et al

in Proc. 1st European IAHR Congress (2010)

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See detailAn Extended Shallow-water-like Model Applied to Flows in Environmental and Civil Engineering
Kerger, François ULiege; Dewals, Benjamin ULiege; Erpicum, Sébastien ULiege et al

in Hirsch, Gerhard; Kappel, Bernd (Eds.) Hydraulic Engineering: Structural Applications, Numerical Modeling and Environmental Impacts (2010)

Objective of this text is to rigorously develop a unified mathematical model to simulate a wide range of environmental flows. Particular emphasis is placed on flows relevant in civil and environmental ... [more ▼]

Objective of this text is to rigorously develop a unified mathematical model to simulate a wide range of environmental flows. Particular emphasis is placed on flows relevant in civil and environmental engineering. [less ▲]

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See detailExperimental investigation of the effect of flip bucket splitters on plunge pool geometry
Erpicum, Sébastien ULiege; Archambeau, Pierre ULiege; Dewals, Benjamin ULiege et al

in Wasserwirtschaft (2010), 4

Flip buckets are common hydraulic structures aiming at deflecting high velocity flows to a free jet trajectory. Systematic experimental tests have been performed to assess the influence on energy ... [more ▼]

Flip buckets are common hydraulic structures aiming at deflecting high velocity flows to a free jet trajectory. Systematic experimental tests have been performed to assess the influence on energy dissipation and the plunge pool geometry of varied repartitions of splitters along the flip bucket width. In particular, it is shown that some configurations can create more erosion than a continuous channel without flip bucket. [less ▲]

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See detailDetailed inundation modelling using high resolution DEMs
Erpicum, Sébastien ULiege; Dewals, Benjamin ULiege; Archambeau, Pierre ULiege et al

in Engineering Applications of Computational Fluid Mechanics (2010), 2(4), 196-208

With the availability of high resolution DEMs, relevant and detailed inundation maps may now be routinely computed provided that suited flow models are available. The full 2D flow model presented in this ... [more ▼]

With the availability of high resolution DEMs, relevant and detailed inundation maps may now be routinely computed provided that suited flow models are available. The full 2D flow model presented in this paper has been used to compute such maps on 800 km of the main rivers of the Walloon Region in Belgium. The use of grid spacing of 1 m, similar to the DEM resolution, enables to accurately predict the pattern of flood depth. This is confirmed by several application examples, which also demonstrate the ability of the model to reproduce depth measurements for a wide range of flood discharges without the need for recalibration of the roughness coefficient. The numerical model has been systematically validated by comparison with observations during recent real flood events. It shows a very good agreement with field data, in particular regarding free surface elevations and inundation extension. [less ▲]

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See detailADAPT - Towards an Integrated Decision Tool for Adaptation Measures - Case study: Floods
Giron, Eve; Coninx, Ingrid; Dewals, Benjamin ULiege et al

Report (2010)

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