References of "Dewals, Benjamin"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailModelling sediment transport over partially non-erodible bottoms
Rulot, François ULg; Dewals, Benjamin ULg; Erpicum, Sébastien ULg et al

in International Journal for Numerical Methods in Fluids (2012), 70(2), 186-199

In depth- and cross section-averaged morphodynamic models, based on explicit time integration, it may happen that the computed bed level becomes lower than the top level of a non-erodible layer (e.g ... [more ▼]

In depth- and cross section-averaged morphodynamic models, based on explicit time integration, it may happen that the computed bed level becomes lower than the top level of a non-erodible layer (e.g. concrete, bedrock or armoured layer). This is a standard pitfall which has been addressed in different ways. In this paper, we present an original approach for avoiding computation of non-physical bed levels, using an iterative procedure to correct the outward sediment fluxes. The procedure is shown to be computationally efficient while it achieves a high accuracy in terms of mass conservation. We compare our original approach with the existing Struiksma’s method and with a reformulation of the problem in terms of mathematical optimization of a linear or non-linear objective function under linear constraints. The new procedure has been incorporated into an existing finite volume morphodynamic model. It has been validated with several 1D benchmarks leading to configurations with sediment transport over non-erodible bottom. The computation time has been verified not to increase by more than 15% compared to runs without non-erodible bottom. [less ▲]

Detailed reference viewed: 110 (37 ULg)
Full Text
Peer Reviewed
See detailTransboundary assessment of the effect of climate change on river Meuse: flood wave selection for hydraulic modelling from Ampsin (B) to Maaseik (NL)
Dewals, Benjamin ULg; Detrembleur, Sylvain ULg; Becker, Bernhard et al

in Proc. 2nd IAHR Europe Congress: Water - infinitely deformable but still limited (2012)

This paper addresses high resolution inundation modelling in a transboundary context. In particular, flood wave propagation and inundation characteristics are simulated over a stretch of almost 100 km of ... [more ▼]

This paper addresses high resolution inundation modelling in a transboundary context. In particular, flood wave propagation and inundation characteristics are simulated over a stretch of almost 100 km of river Meuse across the Belgian-Dutch border, using 2D fully dynamic modelling. This transboundary hydraulic simulation requires inflow hydrographs to be prescribed as upstream boundary conditions. However, existing procedures for generating flood wave hydrographs differ between the concerned regions. Therefore, we review the main characteristics of the existing regional procedures and compare the resulting synthetic hydrographs. Besides, transnational hydrological scenarios have been developed to investigate the impact of climate change on flood risk along river Meuse in both countries. [less ▲]

Detailed reference viewed: 44 (8 ULg)
Full Text
See detailTowards improved operation rules for the Vesdre reservoirs
Detrembleur, Sylvain; Dewals, Benjamin ULg; Erpicum, Sébastien ULg et al

Report (2012)

Detailed reference viewed: 16 (2 ULg)
Full Text
Peer Reviewed
See detailInfluence of the relative alveoli widths on Piano Key Weirs efficiency for varied weir heights
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Proceedings of Int. Symp. on Dams for a changing world (2012)

In the scope of dam rehabilitation to manage floods increase or to increase water storage, the Piano Key Weir is a good solution for concrete dams. Indeed, its labyrinth shape allows discharge capacities ... [more ▼]

In the scope of dam rehabilitation to manage floods increase or to increase water storage, the Piano Key Weir is a good solution for concrete dams. Indeed, its labyrinth shape allows discharge capacities until 4 times more important than traditional ogee-crested weirs and 10 percent more important than labyrinth weirs of same horizontal geometry. Furthermore, the use of up- and downstream overhangs reduces drastically its footprint and enables its use directly on dams crest. The efficiency of Piano Key Weirs is now well demonstrated through various experimental studies. Even if parametrical studies are currently undertaken, the definition of the optimal shape to give to the structure is still missing due to the lack of knowledge in the influence of the large set of geometrical parameters. This paper presents the results of a combine experimental and numerical study about the influence of the relative alveoli widths on the Piano Key Weir discharge capacity. 14 models have been tested providing results for a large range of the inlet to outlet widths ratio and considering variation of the weir height in accordance with former studies. The results of the experiments enable to define optimal values for a common variation of these two parameters. [less ▲]

Detailed reference viewed: 43 (5 ULg)
Full Text
Peer Reviewed
See detailComposite modeling to enhance hydraulic structures studies
Erpicum, Sébastien ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Proceedings of SimHydro 2012 (2012)

Physical modeling and numerical modeling are two efficient analysis approaches in hydraulic engineering. The interactive application of both methods is obviously the more effective response to most flow ... [more ▼]

Physical modeling and numerical modeling are two efficient analysis approaches in hydraulic engineering. The interactive application of both methods is obviously the more effective response to most flow problems analyses. Indeed, it enables combining the inherent advantages of both approaches, which are complementary, while being beneficial to the delays as well as the quality of the analysis. The paper presents the way composite modeling is applied for years at the HECE - Laboratory of Engineering Hydraulics (University of Liege) to enhance hydraulic structures studies. Besides numerical model validation for which experimental benchmarks constitute the first reliable data source, simultaneous application of both modeling approaches may be envisaged in three different ways. Composite modeling may be used to increase the scale factor of physical models by reducing the layout of the real structure to be modeled, to provide a better answer to specific problems than a single approach study or to maximize the efficiency of experimental tests by reducing the range of variation of the unknown parameters to be tested. For each of these three issues depicted in the paper, several examples show how the combined use of efficient numerical solvers together with physical scale models enables to increase the overall quality and scope of the analyses while decreasing the delays and possibly the costs. [less ▲]

Detailed reference viewed: 14 (2 ULg)
Full Text
Peer Reviewed
See detailOn the Piano Key Weir hydraulics
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Rutschmann, Peter; Grünzner, Markus; Stephan, Hötzl (Eds.) Proceedings of 2nd IAHR Europe Congress (2012)

The Piano Key Weir (PKW) is a kind of labyrinth weir with a geometry that uses overhangs to reduce the base length. The PKW can thus be directly placed on the crest of an existing dam. Together with its ... [more ▼]

The Piano Key Weir (PKW) is a kind of labyrinth weir with a geometry that uses overhangs to reduce the base length. The PKW can thus be directly placed on the crest of an existing dam. Together with its high discharge capacity for low heads (up to four times as high as an ogee-crested weir of same length), this geometric feature makes the PKW an interesting solution for dam rehabilitation and for new dam projects with a high level of constraints (design discharge, available space, reservoir storage, ...). PKW has been initially designed in 2001 and built for the first time in 2006 by “Electricité de France (EDF)”. Even if the first experimental studies confirmed its appealing discharge capacities, the flow upstream, over and downstream of this complex structure is still poorly described. Following a 3 years intensive experimental and numerical study of PKW hydraulics, the paper presents a general description of the hydraulic behavior of the PKW. It aims to explain the influence of the large set of geometric parameters on the discharge capacity. The assumptions of the study link various phenomenons depicted in the literature about PKW and an evaluation of their relative influence on the PKW efficiency is given. The role of the crests shape, the crests submersion, the nappes interactions, the crests approach conditions, the position of the control section and the head losses are analyzed. Design advices are also given. [less ▲]

Detailed reference viewed: 44 (8 ULg)
Full Text
Peer Reviewed
See detailInfluence of weir height and keys slope on PKW discharge
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Proceedings of 4th IAHR International Symposium on Hydraulic Structures (2012)

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. Even if former studies highlighted the main influence of the weir height on its discharge capacity, the distinction between weir height effect and keys slope one is not so straight forward. In order to distinguish the influence of these two parameters, the use of parapet walls has been tested to increase weir height keeping bottom slope constant, and to decrease keys slope keeping the weir height constant. The experimental results presented in this paper enable to distinguish the relative influences of the keys bottom slope 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 ▲]

Detailed reference viewed: 45 (5 ULg)
Full Text
Peer Reviewed
See detailComposite modeling to enhance hydraulic structures studies
Erpicum, Sébastien ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Houille Blanche (2012), 6

Physical modeling and numerical modeling are two efficient analysis approaches in hydraulic engineering. The interactive application of both methods is obviously the more effective response to most flow ... [more ▼]

Physical modeling and numerical modeling are two efficient analysis approaches in hydraulic engineering. The interactive application of both methods is obviously the more effective response to most flow problems analyses. Indeed, it enables combining the inherent advantages of both approaches, which are complementary, while being beneficial to the delays as well as the quality of the analysis. The paper presents the way composite modeling is applied for years at the HECE - Laboratory of Engineering Hydraulics (University of Liege) to enhance hydraulic structures studies. Besides numerical model validation for which experimental benchmarks constitute the first reliable data source, simultaneous application of both modeling approaches may be envisaged in three different ways. Composite modeling may be used to increase the scale factor of physical models by reducing the layout of the real structure to be modeled, to provide a better answer to specific problems than a single approach study or to maximize the efficiency of experimental tests by reducing the range of variation of the unknown parameters to be tested. For each of these three issues depicted in the paper, several examples show how the combined use of efficient numerical solvers together with physical scale models enables to increase the overall quality and scope of the analyses while decreasing the delays and possibly the costs. [less ▲]

Detailed reference viewed: 11 (3 ULg)
Full Text
Peer Reviewed
See detailHybride Modellierung deichbruchinduzierter Strömungen
Roger, Sebastian; Dewals, Benjamin ULg; Schüttrumpf, Holger

in Wasserwirtschaft (2012), (12), 31-37

Experimentelle Modellversuche und numerische Simulationen ergänzen sich gegenseitig in einem hybriden Untersuchungskonzept für deichbruchinduzierte Strömungen. Unter Berücksichtigung der ... [more ▼]

Experimentelle Modellversuche und numerische Simulationen ergänzen sich gegenseitig in einem hybriden Untersuchungskonzept für deichbruchinduzierte Strömungen. Unter Berücksichtigung der deichbruchspezifischen Randbedingungen werden in Laborversuchen charakteristische Strömungsfeldgrößen mit hochgenauer Messtechnik detailliert aufgezeichnet. Die korrespondierenden numerischen Modellierungen werden auf Basis der zweidimensional tiefengemittelten Flachwassergleichungen sowie der Reynolds-gemittelten Navier-Stokes-Gleichungen durchgeführt. [less ▲]

Detailed reference viewed: 13 (2 ULg)
Full Text
Peer Reviewed
See detailMethod for the preliminary design of Piano Key Weirs
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Houille Blanche (2012), 4

The Piano Key Weir (PKW) is a particular geometry of weir associating to a labyrinth shape the use of overhangs to reduce the basis length. The PKW could thus be directly placed on a dam crest. Together ... [more ▼]

The Piano Key Weir (PKW) is a particular geometry of weir associating to a labyrinth shape the use of overhangs to reduce the basis length. The PKW could thus be directly placed on a dam crest. Together with its important discharge capacity for low heads, this geometric feature makes the PKW an interesting solution for dam rehabilitation. However, its hydraulic design remains problematic, even at a preliminary stage. This paper presents a preliminary design method based on results of experimental tests. The method enables to design project models by extrapolation of characteristics of existing idealized scale models. A practical application is presented to illustrate the method. [less ▲]

Detailed reference viewed: 154 (3 ULg)
Full Text
Peer Reviewed
See detailExperimental study of velocity fields in rectangular shallow reservoirs
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Journal of Hydraulic Research (2012), 50(4), 435-436

The Authors of the discussed paper present the results of an experimental study to improve the flow classification in rectangular shallow reservoirs. Although previous papers have paved the way for this ... [more ▼]

The Authors of the discussed paper present the results of an experimental study to improve the flow classification in rectangular shallow reservoirs. Although previous papers have paved the way for this classification (Dewals et al. 2008, Dufresne et al. 2010), the Authors are complemented for the detailed flow field measurements conducted for a high number of reservoir geometries. For the tested hydraulic conditions, the Authors report a transition zone corresponding to an ‘unstable’ flow pattern. Repeated tests under similar conditions lead alternately to a symmetric or an asymmetric flow field. In this discussion, it is intended below to shed light on this transition zone using 2D numerical simulations. The Authors state that the flow in the transition zone is sensitive to so-called ‘external perturbations’, whereas we argue that the flow is particularly influenced by the initial test conditions. Using a particular post-processing of the computed flow fields, a hysteresis effect is detected. [less ▲]

Detailed reference viewed: 69 (20 ULg)
Full Text
Peer Reviewed
See detailSemi-explicit modelling of watersheds with urban drainage systems
Dewals, Benjamin ULg; Archambeau, Pierre ULg; Khuat Duy, Bruno et al

in Engineering Applications of Computational Fluid Mechanics (2012), 6(1), 46-57

A trade-off methodology has been developed to account for impervious surfaces and drainage effects accurately, without the need for modelling the entire drainage network in detail. Undrained impervious ... [more ▼]

A trade-off methodology has been developed to account for impervious surfaces and drainage effects accurately, without the need for modelling the entire drainage network in detail. Undrained impervious areas have been distinguished from drained ones. Rain falling on the former has been discharged as overland flow, whereas flow on the later has been routed separately using “virtual pipes”, which enable a simplified process-oriented modelling of the drainage network. [less ▲]

Detailed reference viewed: 140 (41 ULg)
Full Text
Peer Reviewed
See detailQuantifying flood damages for climate-change adaptation on a transnational river basin
Fournier, Maïté; Sinaba, Benjamin; Dewals, Benjamin ULg et al

in Schüttrumpf (Ed.) Floods: a permanent challenge! (2012)

The Meuse river basin is shared by five countries. Climate change in the future decades could either lead to a dryer or a wetter situation. In order to build an adaptation strategy that would cope with ... [more ▼]

The Meuse river basin is shared by five countries. Climate change in the future decades could either lead to a dryer or a wetter situation. In order to build an adaptation strategy that would cope with both scenarios and that is agreed at the international level, water experts have set-up the AMICE project. Quantifying the flood damages is an important part of this project. It required much negotiation at every intermediary step, from the definition of climate scenarios, to the hydraulic modeling and the agreement on damage functions. [less ▲]

Detailed reference viewed: 52 (2 ULg)
Full Text
See detailOn the advantage of using risk curves to assess flood protection measures
Dewals, Benjamin ULg; Detrembleur, Sylvain ULg; Archambeau, Pierre ULg et al

in Mambretti, Stefano (Ed.) Environmental Risk (2012)

Modern flood management approaches require the quantification of flood risk, accounting for the hazard component (flood frequency and inundation intensity) as well as the vulnerability of the floodplains ... [more ▼]

Modern flood management approaches require the quantification of flood risk, accounting for the hazard component (flood frequency and inundation intensity) as well as the vulnerability of the floodplains (exposure, value and susceptibility). In this chapter, we present a detailed flood risk model, in which flow computation, monetary valuation of the assets and damage calculation are conducted at the scale of individual buildings or facilities. To avoid the shortcoming of focusing on economic damage, psycho-social impacts of floods are also included in the analysis. The model has been applied to evaluate three flood protection measures on a river reach in the Meuse basin (Belgium). The resulting risk curves show that such a micro-scale risk analysis provides important insights into the relative influence of the different flood protection measures. This could neither be evaluated through a more standard hydraulic analysis nor through the quantification of flood risk by only a single number. [less ▲]

Detailed reference viewed: 25 (4 ULg)
Full Text
Peer Reviewed
See detailConsidering non-alluvial layers in morphodynamic modelling
Rulot, François ULg; Erpicum, Sébastien ULg; Dewals, Benjamin ULg et al

Conference (2011, November)

Detailed reference viewed: 7 (3 ULg)
Full Text
Peer Reviewed
See detailHydromorphological restoration of Alpine rivers
Rulot, François ULg; Dewals, Benjamin ULg; Erpicum, Sébastien ULg et al

Conference (2011, November)

More and more efforts are undertaken to restore rivers in a state close to their natural conditions in order to meet the Water Framework Directive requirement. This directive commits EU member states to ... [more ▼]

More and more efforts are undertaken to restore rivers in a state close to their natural conditions in order to meet the Water Framework Directive requirement. This directive commits EU member states to achieve a good ecological status of all their water bodies. It became thus very important to develop river restoration such as fish passages, bank renaturation, natural bars or meanders. Another important component of river restoration schemes is the decommissioning of man-made structures. These interventions can have significant impact on the river hydrology, hydraulics and morphology, such as bed degradation or aggradation, bank failures. Predicting these impacts of restoration schemes on the river, especially for large scale projects, should rely on detailed numerical studies. To achieve this goal, we develop a methodology to analyse different scenarios of river restoration based on several criteria related to flow, sediment transport and environment. This method is applied to the case of a French alpine river in which five hydropower plants will be replaced by a unique underground hydropower plant on the same section of river. [less ▲]

Detailed reference viewed: 6 (0 ULg)