References of "Dewals, Benjamin"
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See detailExperimental analysis of the stability of coarse sediments
Duma, Diana ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Symposium on Two-phase Modelling for Sediment Dynamics in Geophysical Flows (2013, June 12)

To predict the inception of sediment motion, Shields diagram remains the most widely used criterion in engineering practice so far. However, this approach faces several limitations and a number of gaps in ... [more ▼]

To predict the inception of sediment motion, Shields diagram remains the most widely used criterion in engineering practice so far. However, this approach faces several limitations and a number of gaps in knowledge still remain. The present research aims to provide new knowledge about the inception of motion in rivers with coarse sediments. A series of experiments was conducted in a flume horizontal 6 m long and 15 cm wide. The bottom was paved, either entirely or partly, with gravels of approximately 12 mm in diameter. Ultrasonic sensors were used to measure the water depth, a flowmeter for the discharge, an ultrasonic velocity profiler (UVP) transducer for the flow velocity. Three different thresholds were defined to distinguish between the following states: no motion, vibration of stones, local motion, and large scale motion. The overwhelming influence of turbulence was emphasized by the conducted tests. This paper details the results of these experiments and demonstrates the need for further research in order to better quantify these effects. [less ▲]

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See detailParapet wall effect on Piano Key Weirs efficiency
Machiels, Olivier; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Journal of Irrigation & Drainage Engineering (2013), 139(6), 506-511

Piano Key Weir is a cost effective solution for rehabilitation as well as for new dam projects with a high level of constraints (limited space, high specific flood discharge, small reservoir level ... [more ▼]

Piano Key Weir is a cost effective solution for rehabilitation as well as for new dam projects with a high level of constraints (limited space, high specific flood discharge, small reservoir level variation). While the higher efficiency of the Piano Key Weir compared to standard linear weirs has already been demonstrated, its optimal geometry is still poorly defined. In order to improve the design of the complex geometry of this structure, the use of parapet walls has been tested. They consist of vertical extensions placed over the weir crest. Following a former study of the influence of the weir height on its discharge capacity, this paper presents the results of an experimental campaign dedicated to investigating the effect of parapet walls to increase weir height while reducing bottom slopes and keeping the weir height constant. These results indicate the relative influences of the alveoli bottom slopes and of the weir height on the Piano Key Weir release capacity. Comparisons with former experimental results as well as design guidelines are also provided. [less ▲]

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See detailHydraulic modelling in civil and environmental engineering
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

Scientific conference (2013, May 08)

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See detailModélisation numérique hydrosédimentaire au service de la gestion durable des sédiments
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Recyclage et Valorisation (2013), 41

La gestion des sédiments revêt une importance croissante pour l’exploitation des voies navigables et nombre de projets de construction de barrages et de complexes hydroélectriques. L’impact des apports en ... [more ▼]

La gestion des sédiments revêt une importance croissante pour l’exploitation des voies navigables et nombre de projets de construction de barrages et de complexes hydroélectriques. L’impact des apports en matériaux solides se manifeste tant par des effets à long terme, telle la réduction de la capacité du réservoir, que par des conséquences à plus court terme, telle l’usure prématurée des turbines. L’étude détaillée des effets sédimentaires s’impose donc de plus en plus tôt dans la conception de nouveaux aménagements. Elle est aussi un objectif tout au long de l’exploitation des ouvrages, dans une perspective de gestion sécuritaire et durable. [less ▲]

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See detailEffects of climate change on the river Meuse: Hydraulic 2D modeling from Amspin to Maaseik (and beyond)
Huismans, Ymkje; Dewals, Benjamin ULg; van der Mark, Rolien et al

Poster (2013, March 22)

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See detailScientific basis for transnational flood management in the Meuse basin
Dewals, Benjamin ULg; Huismans, Ymkje; Detrembleur, Sylvain et al

Conference (2013, March 22)

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See detailImpact of climate change on inundation hazard along the river Meuse
Dewals, Benjamin ULg; Drogue, Gilles; Erpicum, Sébastien ULg et al

in Transboundary Water Management in a Changing Climate (2013, March)

As a part of the effort to scientifically inform the development of the adaptation strategy for the Meuse basin, we detail hereafter the generation of integrated climate and hydrological scenarios for the ... [more ▼]

As a part of the effort to scientifically inform the development of the adaptation strategy for the Meuse basin, we detail hereafter the generation of integrated climate and hydrological scenarios for the whole basin. We also present the setup of a first coordinated hydraulic modelling from spring to mouth of the river Meuse. The latter has enabled to compute the range of change in inundation hazard under the “wet” transnational hydrological scenario for the time slices 2021-2050 and 2071-2100. A significantly higher impact of climate change has been found in the middle part of the Meuse basin, compared to the upper and the lower parts. These conclusions have been further confirmed by a refined analysis conducted for a 100 km-long stretch of the river Meuse crossing the Belgian-Dutch border. [less ▲]

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See detailEvolution du risque lié aux inondations de la Meuse : Influences relatives du climat et de la croissance des zones résidentielles
Beckers, Arnaud ULg; Detrembleur, Sylvain; Dewals, Benjamin ULg et al

Scientific conference (2013, February 28)

Chaque année, les inondations par débordement des rivières provoquent des dommages significatifs en Wallonie. L’ampleur de ceux-ci est liée à l’importance des crues elles-mêmes, mais aussi à l’occupation ... [more ▼]

Chaque année, les inondations par débordement des rivières provoquent des dommages significatifs en Wallonie. L’ampleur de ceux-ci est liée à l’importance des crues elles-mêmes, mais aussi à l’occupation du sol des terrains inondés. Dans le contexte des changements climatiques, comment évolueront les débits des crues « extrêmes » ? Quelle pourrait être l’influence de l’évolution de l’occupation du sol sur les dommages ? La vallée de la Meuse a été choisie pour investiguer et concrétiser les réponses à ces questions. Les dommages liés à une crue centennale ont été calculés pour la situation actuelle ainsi que pour différentes situations potentielles en 2100, suivant un scénario d’évolution climatique et neuf scénarios d’urbanisation de la Wallonie. L'accent sera mis sur tant sur le développement de ces scénarios que sur les conclusions robustes tirées des résultats obtenus en termes d’influence relative du climat et de l’occupation du sol sur les dommages futurs. [less ▲]

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See detailPhysical and numerical modelling in low-head structures design
Dewals, Benjamin ULg; Archambeau, Pierre ULg; Rulot, François ULg et al

in Bung, Daniel; Pagliara, Stefano (Eds.) Proceedings of the International Workshop on Hydraulic Design of Low-Head Structures (2013, February)

Physical and numerical modelling may be combined within so-called composite or hybrid modelling. This enables to optimally take benefit of the respective strengths of each modelling approach, while ... [more ▼]

Physical and numerical modelling may be combined within so-called composite or hybrid modelling. This enables to optimally take benefit of the respective strengths of each modelling approach, while compensating for their specific drawbacks. Different types of composite modelling may be identified, such as embedding a detailed physical model within a broader scale numerical model, interconnecting different physical and numerical models focusing each on specific processes, or validating a numerical model from experimental data before exploiting the numerical model to generate more results than availa-ble from the experimental facility. Besides, specifically in more basic research, composite modelling may also be used to improve in-depth understanding of the relative importance of different processes which act simultaneously in the experimental test and may be artificially separated in numerical simulations. [less ▲]

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See detailStepped spillway Downstream of a Piano Key Weir - Critical length for uniform flow
Silvestri, Aurélien ULg; Pirotton, Michel ULg; Erpicum, Sébastien ULg et al

in Bung, Daniel B.; Pagliara, Stefano (Eds.) International Workshop on Hydraulic Design of Low-Head Structures (2013)

Recent researches showed the rapid aeration of the flow downstream of piano key weirs. This could be related to the specific geometric features of the structure, creating several interacting flows and ... [more ▼]

Recent researches showed the rapid aeration of the flow downstream of piano key weirs. This could be related to the specific geometric features of the structure, creating several interacting flows and jets downstream. In order to validate this assumption, an experimental research has been carried out at the Laboratory of Engineering Hydraulics, University of Liège. The main objective of the study was to an-alyze the energy dissipation occurring in skimming flow conditions on a stepped spillway downstream of a piano key weir (PKW). Comparison with energy dissipation on a stepped spillway downstream of a standard ogee crested weir has been performed. An indirect method has been used to determine the resid-ual energy at the spillway toe. The results show that uniform flow conditions are reached faster on a stepped spillway downstream of a PWK compared to the length needed downstream of a standard ogee crested weir. Extrapolation of the results to prototype flow conditions is also discussed with regards to scale effects influence. [less ▲]

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See detailComparative analysis of the energy dissipation on a stepped spillway downstream of a Piano Key Weir
Silvestri, Aurélien ULg; Archambeau, Pierre ULg; Pirotton, Michel ULg et al

in Erpicum, Sébastien; Laugier, Frédéric; Pfister, Michael (Eds.) et al Labyrinth and Piano Key Weirs II - PKW 2013 (2013)

A systematic experimental study has been carried out to compare the residual energy at the toe of a stepped spillway of varied length considering a classical ogee-crested weir (OCW) or two different piano ... [more ▼]

A systematic experimental study has been carried out to compare the residual energy at the toe of a stepped spillway of varied length considering a classical ogee-crested weir (OCW) or two different piano key weirs (PKW) at the top of the structure. Four spillway lengths have been considered on a wide range of discharge. An indirect method has been used to compute the residual flow energy at the spillway toe from water depth measurements in a horizontal channel downstream. The results indicate that uniform flow conditions, i.e. flow energy at the spillway toe independent of the spillway length, are reached on significantly shorter spillways downstream of a PKW than downstream of an OCW. However, the uniform flow energy at constant discharge on the spillway is found to vary depending on the weir type. In particular, it is smaller downstream of the OCW than downstream of the PKWs. [less ▲]

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See detailDike-break induced flows: a simplified model
Stilmant, Frédéric ULg; Pirotton, Michel ULg; Archambeau, Pierre ULg et al

in Environmental Fluid Mechanics (2013), 13(1), 89-100

A simplified model for the prediction of the steady-state outflowthrough a breach in an inland dike is presented. It consists in the application of the mass and momentum conservation principles to a ... [more ▼]

A simplified model for the prediction of the steady-state outflowthrough a breach in an inland dike is presented. It consists in the application of the mass and momentum conservation principles to a macroscopic control volume. A proper definition of the shape of the control volume enables to take the main characteristics of the flow into account and thus to compensate for the extreme simplification of the spatial representation of the model. At the breach, a relation derived from the shallow-water equations is used to determine the direction of the flow. Developments have been guided by numerical simulations and results have been compared to experimental data. Both the accuracy and the domain of validity of the simplified model are found satisfactory. [less ▲]

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