References of "Dewals, Benjamin"
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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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See detailBlood Flow under External Strains; Phenomenological Approach, Theoretical Developments & Numerical Analysis
Paulus, Raphaël ULg; Erpicum, Sébastien ULg; Dewals, Benjamin ULg et al

in International Journal of Design & Nature and Ecodynamics (2010), 78

In the medical field, the measurement of blood flow characteristics is often necessary. More specifically, blood pressure is an essential measure when it comes to assessing health. All over the world ... [more ▼]

In the medical field, the measurement of blood flow characteristics is often necessary. More specifically, blood pressure is an essential measure when it comes to assessing health. All over the world, many people suffer from hyper- or hypotension, and as it is known that these diseases can lead to serious complications, it is of great interest to determine the blood pressure with high accuracy. Nowadays, such information requires the use of specifi c materials; the present method for the measurement of the arterial pressure, by applying pressure using an armband (with a control device called sphygmomanometer), is known to introduce significant errors due to the inadequacy of the band dimensions (both the length and the circumference). The objective of the present research is to study and simulate the discharge of the blood in an artery subjected to external strains using theoretical developments and a numerical approach. Based on these modelling results, the response of the fluid to the external pressure of the band can be studied, and fi nally appropriate corrective factors for the true pressure and the measured pressure could be assessed. This research has been carried out with the aim of sharing medical and engineering views on the subject. The artery can be modelled as a deformable pipe, where the blood fl owing in it is a fl uid with specifi c properties. Thus, two complementary and interconnected domains are covered, solid mechanics (to obtain analytic relations between the strains and the deformations, using either linear or non-linear theories) and fluid mechanics (to study the discharge of blood in a deformable pipe, using finite volume methods), therefore considering the problem as a loose fl uid–structure interaction (FSI). These two domains, which are well studied for common materials in civil engineering applications, are applied here not only to specifi c materials but especially to uncommon structures that, besides the somehow common FSI developments, lead to the investigation and research of very specifi c boundary conditions, giving them a physically based behaviour. At present, the research has reached the penultimate step, with the two main mentioned axes being fully developed and tested on their own. In particular, the boundary conditions developed for the models have been investigated and modelled in depth. [less ▲]

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See detailModélisation numérique 2D unifiée des écoulements sur des évacuateurs de crue avec déversoir
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg et al

in Houille Blanche (2010), (6), 102-108

The hydrodynamic modelling system WOLF 2D enables to combine different hydrodynamic sub-models within one single computation domain. For instance, for the purpose of simulating flows in the vicinity of ... [more ▼]

The hydrodynamic modelling system WOLF 2D enables to combine different hydrodynamic sub-models within one single computation domain. For instance, for the purpose of simulating flows in the vicinity of spillways, the following three hydrodynamic sub-models are interconnected: (i) a conventional “shallow-water” model, (ii) a suitable model for the simulation of the flow on the topographic step directly upstream of the spillway and (iii) a model able to accurately account for the bottom curvature near the spillway crest, along the spillway and at its bottom. In the latter model, based on curvilinear coordinates in the vertical plane, takes into consideration not only the bottom slope but also the bottom curvature in the vertical plane. As a result, the velocity profile along the water depth is generalized compared to the uniform profile usually assumed in the standard shallow-water equations and the pressure distribution is also modified as a function of the bottom curvature and is thus not purely hydrostatic but accounts for the effect of centrifugal forces. This extended mathematical model has been implemented within the modelling system WOLF 2D, based on a new finite volume scheme. Several validation examples and a real application demonstrate the accuracy and the practical applicability of the new model. [less ▲]

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See detailEffondrement d’un mur de berge sur la Vesdre
Dewals, Benjamin ULg

in Interview on the Belgian radio RTBF (2010)

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See detailFlood risk analysis in Wallonia: micro (and meso-)scale approaches
Dewals, Benjamin ULg; Detrembleur, Sylvain ULg; Archambeau, Pierre ULg et al

Conference (2010, October 25)

Flood risk analysis has been undertaken in Wallonia in the framework of several national and international research projects. The analysis relies on a micro-scale procedure, which involves • hazard ... [more ▼]

Flood risk analysis has been undertaken in Wallonia in the framework of several national and international research projects. The analysis relies on a micro-scale procedure, which involves • hazard modelling by means of detailed 2D inundation modelling • as well as processing of high resolution topographic and land use database for vulnerability modelling. The inundation modelling is conducted using the fully dynamic flow model WOLF 2D, entirely developed at the University of Liege. The model is run on a highly accurate DEM resulting from the combination of laser altimetry and, when available, sonar bathymetry. The typical grid spacing for the simulations is kept as low as 2m, which is definitely fine enough to represent the complex flows occurring at the scale of individual buildings and streets in urbanized floodplains. In this way, both the static and dynamic impacts of the flow may be characterized for all affected assets. This approach has been extensively applied since 2003 to issue inundation maps throughout the Walloon region based on detailed 2D flow modelling. Consequently, the outcomes of such detailed inundation modelling constitute suitable inputs for the subsequent exposure analysis, performed at a micro-scale using detailed land use maps and geographic database. Eventually, based on a multidisciplinary work, the procedure may incorporate social flood impact analysis and evaluation of direct economic damage to different categories of buildings and land types. Besides detailing the characteristics and performance of the hazard modelling, the presentation will describe the flow of data within the overall risk analysis procedure and will demonstrate its applicability by means of a case study, for which three different flood protection measures have been evaluated. These include rehabilitation of an old canal, recalibration of a floodplain as well as heightening of a protection wall by means of mobile dikes. The risk-oriented analysis of these flood protection measures has lead to findings which would not have arisen from a more standard hydraulic study such as based on a design flood. The flood risk analysis procedure is now readily available for large scale applications throughout the hydrographic basins in Wallonia and, in the near future, it will be combined with catchment modelling (accounting for climate change projections) to evaluate upstream flood mitigation measures as well as for the fine tuning of reservoir management rules in the framework of adaptation strategies to climate change. [less ▲]

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See detailHydropower: An Essential Partner of Renewable Energy Source
Lejeune, André ULg; Hui, Samuel; Pirotton, Michel ULg et al

in Sayigh, Ali (Ed.) World Renewable Energy Congress XI (2010, September 25)

In 2006, the 17 percent of the world’s electricity that was generated from hydropower represented nearly 90 percent of renewable electricity generation worldwide; Hydropower is an important source of ... [more ▼]

In 2006, the 17 percent of the world’s electricity that was generated from hydropower represented nearly 90 percent of renewable electricity generation worldwide; Hydropower is an important source of renewable energy and produces extremely small quantities of carbon dioxide. Between 1998 and 2008, renewable electricity production in the world rose from 2,794.9 to 3,762.6 TWh, i.e. an additional 967.6 TWh. As a final conclusion, despite hydropower’s high initial costs, its long-term overall costs tend to be low. The average cost of electricity production by hydropower is still very attractive for the moment. In the next future, hydropower will keep his position, in front of the other renewable sources of electricity, on the same level with biomass, better that wind power and much cheaper than solar energy. [less ▲]

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See detailExperimental investigation of flow pattern and sediment deposition in rectangular shallow reservoirs
Dufresne, Matthieu; Dewals, Benjamin ULg; Erpicum, Sébastien ULg et al

in International Journal of Sediment Research (2010), 25(3), 258-270

This work involved the experimental investigation of flow pattern, preferential regions of deposition and trap efficiency as a function of the length of rectangular shallow reservoirs. Four flow patterns ... [more ▼]

This work involved the experimental investigation of flow pattern, preferential regions of deposition and trap efficiency as a function of the length of rectangular shallow reservoirs. Four flow patterns were identified (from longer to shorter reservoirs): an asymmetric flow with two reattachment points, an asymmetric flow with one reattachment point, an unstable flow, and a symmetric flow without any reattachment point. Using dye visualizations, the median value and the temporal variability of the reattachment lengths were precisely measured for the asymmetric flows. For each stable flow, sediment tests with plastic particles were carried out. The regions of deposition on the bed of the reservoir were clearly a function of the flow pattern. The transition from an asymmetric flow pattern to a symmetric flow pattern was responsible for an abrupt decrease of the trap efficiency; a number of regression laws were discussed to take it into account. [less ▲]

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See detailDam-break flow computation based on an efficient flux-vector splitting
Erpicum, Sébastien ULg; Dewals, Benjamin ULg; Archambeau, Pierre ULg et al

in Journal of Computational & Applied Mathematics (2010), 234

Dam-break flow computation is a task of prime interest in the scope of risk analysis processes related to dams and reservoirs. In this paper, a 2D finite volume multiblock flow solver, able to deal with ... [more ▼]

Dam-break flow computation is a task of prime interest in the scope of risk analysis processes related to dams and reservoirs. In this paper, a 2D finite volume multiblock flow solver, able to deal with natural topography variation, is presented in details. The model is based on an efficient Flux Vector Splitting method developed by the authors. A number of validation examples are comprehensively described. [less ▲]

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See detailProceedings of the International Symposium on Unsteady Sediment Transport - GESINUS 2010
Dewals, Benjamin ULg; Erpicum, Sébastien ULg; Rulot, François ULg et al

Book published by University of Liege (2010)

Complexity in sediment transport and morphological modelling stems specifically from the variety of relevant physical processes as well as from their multi-scale nature, both in space (from grain- to ... [more ▼]

Complexity in sediment transport and morphological modelling stems specifically from the variety of relevant physical processes as well as from their multi-scale nature, both in space (from grain- to catchment scale) and in time (from quasi-instantaneous bank failures to silting of reservoirs within decades). To address this, the HACH group has developed a unique modelling system, which offers high flexibility in coupling flow and sediment transport sub-models to cover the broad spectrum of relevant time scales. In this framework, the HACH has convened on 29 and 30 July 2010 an international symposium, during which recent advances in morphological modelling have been presented, as well as progresses in grain scale experiments and field measurements. The symposium was supported by the University of Liege and the Fund for Scientific Research FNRS. Contributions from many European countries were presented and discussed, including Austria, Belgium, France, Italy, Netherlands, United Kingdom and Switzerland. [less ▲]

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See detailModeling the vertical spincasting of large bimetallic rolling mill rolls
Studer, Léo ULg; Detrembleur, Sylvain ULg; Dewals, Benjamin ULg et al

in Key Engineering Materials [=KEM] (2010, June), 443

In order to take into account the dynamic effects of molten metal during solidification, a methodology is presented to interface a metal solidification solver (coupled thermal mechanical metallurgical ... [more ▼]

In order to take into account the dynamic effects of molten metal during solidification, a methodology is presented to interface a metal solidification solver (coupled thermal mechanical metallurgical finite elements solver) with a specifically developed flow dynamics solver. (flow dynamics and thermics finite volume solver) The numerical set of tools is designed to be used for the simulation of bimetallic hot rolling mill rolls vertical spincasting. Modeling the industrial process for these products imply certain specifications on the numerical methods used, mainly due to the size of the geometrical domain, low Rossby & Ekman numbers, and a high Reynolds number. [less ▲]

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See detailAnalysis of climate change, high-flows and low-flows scenarios on the Meuse basin: WP1 report - Action 3
Drogue, G.; Fournier, M.; Bauwens, Alexandra ULg et al

Report (2010)

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See detailRiver modelling and flood mitigation in a Belgian catchment
Khuat Duy, Bruno; Archambeau, Pierre ULg; Dewals, Benjamin ULg et al

in Proceedings of ICE : Water Management (2010), 163(8), 417-423

This paper describes the steps followed to propose solutions to recurring flooding problems in a Belgian catchment. Firstly, the hydraulic capacity (maximum discharge before bank overflow) of the cross ... [more ▼]

This paper describes the steps followed to propose solutions to recurring flooding problems in a Belgian catchment. Firstly, the hydraulic capacity (maximum discharge before bank overflow) of the cross sections was computed all along the river by an iterative 1D steady-state approach. In order to carry out these simulations, cross sections from on-site surveys of the river were integrated into the model, as well as hydraulic structures such as culverts, footbridges, and pipes. Secondly, the flooding problem was analysed with a time-dependant approach consisting of simulating floods following extreme rainfall events. The hydrological aspect was studied in a spatially distributed way using a multi-layer hydrological model. The available data on the basin such as the digital elevation model (DEM), the landuse, and the pedology were exploited to identify the basic modelling parameters. The hydrological contribution was routed by a 1D network resulting from the merging of the DEM-based and the cross section-based river networks. According to the results of the aforementioned steps, various local and catchment-wide solutions against flooding were proposed and analyzed. The comparison of simulated situations before and after these improvements allowed checking the effectiveness of the proposed solutions. [less ▲]

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See detailMicro-scale flood risk analysis based on detailed 2D hydraulic modelling and high resolution geographic data
Ernst, Julien ULg; Dewals, Benjamin ULg; Detrembleur, Sylvain ULg et al

in Natural Hazards (2010), 55(2), 181-209

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. Consequently, the outcomes of hydraulic modelling constitute suitable inputs for the subsequent exposure analysis, performed at a micro-scale using detailed land use maps and geographic database. Eventually, the procedure incorporates social flood impact analysis and evaluation of direct economic damage to residential buildings. Besides detailing the characteristics and performance of the hydraulic model, the paper describes the flow of data within the overall flood risk analysis procedure and demonstrates its applicability by means of a case study, for which two different flood protection measures were evaluated. [less ▲]

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See detailHydraulic behavior of Piano Key Weirs: experimental approach
Machiels, Olivier ULg; Erpicum, Sébastien ULg; Archambeau, Pierre ULg 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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