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See detailModeling the sound transmission coupled through partition walls using a diffusion model
Billon, Alexis ULg; Foy, Cédric; Picaut, Judicaël et al

in Journal of the Acoustical Society of America (2008), 123(6), 4261-4271

In this paper, a modification of the diffusion model for room acoustics is proposed to account for sound transmission between two rooms, a source room and an adjacent room, which are coupled through a ... [more ▼]

In this paper, a modification of the diffusion model for room acoustics is proposed to account for sound transmission between two rooms, a source room and an adjacent room, which are coupled through a partition wall. A system of two diffusion equations, one for each room, together with a set of two boundary conditions, one for the partition wall and one for the other walls of a room, is obtained and numerically solved. The modified diffusion model is validated by numerical comparisons with the statistical theory for several coupled-room configurations by varying the coupling area surface, the absorption coefficient of each room, and the volume of the adjacent room. An experimental comparison is also carried out for two coupled classrooms. The modified diffusion model results agree very well with both the statistical theory and the experimental data. The diffusion model can then be used as an alternative to the statistical theory, especially when the statistical theory is not applicable, that is, when the reverberant sound field is not diffuse. Moreover, the diffusion model allows the prediction of the spatial distribution of sound energy within each coupled room, while the statistical theory gives only one sound level for each room. [less ▲]

Detailed reference viewed: 13 (1 ULg)
See detailModeling the Structural Behavior in Case of Fire
Franssen, Jean-Marc ULg

Scientific conference (1996, July 15)

Detailed reference viewed: 5 (1 ULg)
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See detailModeling the uncertainty of runoff flow path on a small agricultural watershed
Ouedraogo, Mohamar ULg

Scientific conference (2013, July 01)

Recently, many munipalities have been concerned by muddy floods in Belgium after rain events. Unfortunately they lead to many consequences related to financial and emotional aspects. For many years the ... [more ▼]

Recently, many munipalities have been concerned by muddy floods in Belgium after rain events. Unfortunately they lead to many consequences related to financial and emotional aspects. For many years the government have been trying to find solutions by helping municipalities by providing them with technical support through projects like ERRUISSOL and GISER. To implement solutions, it is necessary to be able to predict runoff flow path on agricultural watersheds. This is done by applying water flow direction algorithms on digital elevation model (DEM) built from elevation data. However, digital elevation models are not free of errors, and therefore they can impact the extracted flow path position. Our aim is to present the Monte Carlo simulation that is used to model the uncertainty of runoff flow path extracted from high resolution DEM built from terrestrial laser scanner. [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 Ambrosio, J. (Ed.) Proceedings of the 7th EUROMECH Solid Mechanics Conference (2009)

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 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 ▲]

Detailed reference viewed: 67 (19 ULg)
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See detailModeling thixoforming process using the eXtended Finite Element Method and the Arbitrary Lagrangian Eulerian formulation
Biotteau, Ewen; Bussetta, Philippe ULg; Ponthot, Jean-Philippe ULg

in Key Engineering Materials [=KEM] (2013), 554-557

In this contribution, one proposes a new strategy to model forming processes involving non-linear phenomena. The contact between the tool and the structure is enforced using a penalty approach. To free ... [more ▼]

In this contribution, one proposes a new strategy to model forming processes involving non-linear phenomena. The contact between the tool and the structure is enforced using a penalty approach. To free the user from the strict conforming between the structure and the mesh boundaries, one uses the level set and the extended finite element method for material/void interfaces. However, even if the finite element mesh does not need to conform with the boundaries, it still deforms with the structure. Then, an Arbitrary Lagrangian Eulerian formulation is introduced to relocate the mesh in its initial configuration and avoid distortions. From a user point of view, the whole calculation is then performed on a fixed Eulerian mesh. [less ▲]

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See detailModeling tracer injection and well-aquifer interactions: A new mathematical and numerical approach
Brouyère, Serge ULg

in Water Resources Research (2003), 39(3),

[1] A new mathematical and numerical approach is presented to model solute exchange between a well and the surrounding aquifer for the interpretation of field tracer tests. On the basis of water and ... [more ▼]

[1] A new mathematical and numerical approach is presented to model solute exchange between a well and the surrounding aquifer for the interpretation of field tracer tests. On the basis of water and tracer mass balance equations integrated over the volume of water in the well, the approach allows for finite volumes of tracer fluid and water flush. It deals with tracer mixing and capturing in the well bore, local distortion of the flow field around the well, and possible tracer back-migration into the well. A numerical solution, implemented in the three-dimensional finite element groundwater flow and transport simulator SUFT3D, is proposed that allows for modeling nonuniform distributions of tracer mass fluxes along the well screens related to variations in aquifer hydraulic conductivity. Showing its ability to reproduce concentration evolutions monitored in a well during field tracer experiments, considering various injection conditions, validates the approach. [less ▲]

Detailed reference viewed: 46 (11 ULg)
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See detailModeling travel behavior: Whether weather matters
Cools, Mario ULg

Speech (2013)

Detailed reference viewed: 32 (5 ULg)
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See detailModeling using the SWAT model of water flow and transport in suspension in the watershed of the valley of Wadi El-Hachem
Tadrist, Nassima ULg; DEBAUCHE, OLIVIER ULg; Degré, Aurore ULg et al

Poster (2014, May 12)

In the Maghreb, dams regularly suffer from excessive siltation due to erosion problems present in the catchment areas. The origins of this erosion are multiple: land use, deforestation, land affectation ... [more ▼]

In the Maghreb, dams regularly suffer from excessive siltation due to erosion problems present in the catchment areas. The origins of this erosion are multiple: land use, deforestation, land affectation , ... Hydrology coupled with geographic information systems allows using distributed and physically based models to predict the evolution of siltation of dams. The application of these models in Algeria will finally predict the impact of anti-erosion measures, land use patterns on the siltation of dams accurately estimating the amount of sediment produced by erosion runoff and the degree of filling. A methodology based on the map data (digital terrain model, map soil science, geology map and mapping of land use) and daily meteorological data (temperature, relative humidity, wind speed, solar radiation) is being development and testing of the dam Bourkourdane. The SWAT model is used to predict the amount of sediment accumulating in the dam, the water flow rate inbound, outbound, and the volumes of water and sediment stored in the dam. Adequate management of releases, coupled with better management of erosion upstream of the dam will extend the life of dams Algerians. Especially for Boukourdane, improved management of releases is paramount to improve groundwater recharge, fight against the intrusion of marine waters and prevent the accumulation of fine particles that reduce soil permeability. [less ▲]

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See detailMODELING WASTEWATER SLUDGE DRYING WITH DETERMINATION OF DIFFUSIVITY MOISTURE
Bennamoun, Lyes ULg; Fraikin, Laurent ULg; Salmon, Thierry ULg et al

Scientific conference (2012, September 06)

Convective drying of two different types of wastewater sludges is investigated. Experiments are realised in a micro-dryer, for air temperatures of 80 °C, 140 °C and 200 °C, the velocity and humidity ... [more ▼]

Convective drying of two different types of wastewater sludges is investigated. Experiments are realised in a micro-dryer, for air temperatures of 80 °C, 140 °C and 200 °C, the velocity and humidity remaining the same. The product drying kinetics presents, for all studied cases, three main phases, which are: adaptation phase, constant drying rate phase and falling drying rate. A comparison between two mathematical approaches allows determination of the diffusion coefficient. The value of this coefficient depends on the origin of the wastewater sludge and the operating temperatures. Physical changes such as shrinkage are introduced into the mathematical model. [less ▲]

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See detailModélisation 2D par éléments finis du contact : effet de l’utilisation de méthodes de représentation des surfaces présentant un ordre de continuité élevé et méthodes permettant de passer le patch test
Nguyen, Duc Tue ULg

Doctoral thesis (2014)

Ce travail de thèse concerne la mécanique numérique du contact entre les solides déformables. La simulation numérique des problèmes de contact comporte de nombreuses difficultés notamment dans un contexte ... [more ▼]

Ce travail de thèse concerne la mécanique numérique du contact entre les solides déformables. La simulation numérique des problèmes de contact comporte de nombreuses difficultés notamment dans un contexte de grands déplacements et de grandes déformations. Le but de ce travail est d’analyser l’influence de l’ordre de continuité élevé de la représentation de surface et de développer une méthode pour passer le patch test, à savoir qu’un élément passe le patch test si il transmet correctement des pressions de contact entre deux surfaces. Pour la discrétisation des éléments finis, l'interface de contact est représentée par une série de lignes et de courbes à continuité C0. Par conséquent, lors du passage du nœud esclave entre deux segments maîtres adjacents, il peut arriver avoir une discontinuité de la direction du vecteur normal. Cette situation peut mener à des problèmes de convergence de l'algorithme de résolution. Pour éviter ce problème, l’approche proposée consiste à développer les représentations de surface maître à ordre de continuité C1 ou C2 pour les éléments nœud-surface linéaires et quadratiques. Les éléments nœud-surface ne passent pas le patch test. Plus récemment, un élément linéaire utilisant la méthode des nœuds esclaves virtuels pour Passer le Patch Test (PPT) a été proposée dans la littérature. Cependant, cet élément est à ordre de continuité C0 et peut donner des grandes oscillations de la pression de contact à cause des pénétrations initiales des nœuds esclaves virtuels qui sont les pénétrations des nœuds esclaves virtuels dans la surface maître à l’état initial. Pour tenter de surmonter cette difficulté, une nouvelle approche repose sur un élément linéaire utilisant la méthode PPT et la représentation de surface à ordre de continuité C1 pour la surface maître et pour la surface esclave. L’élément quadratique nœud-surface donne des oscillations de pression de contact à cause de la distribution non-uniforme des forces nodales. Afin de résoudre ce problème, la méthode PPT est développée pour l’élément quadratique. [less ▲]

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See detailModélisation 3D d’un groupe de pieux pour le pont-canal de Houdeng
Trevisan, Stefano; Li, Xian Ling; Collin, Frédéric ULg et al

in Revue Française de Géotechnique (2003), 105

A satisfactory prediction of the settlements of hyperstatic structures is becoming more and more important in their design and construction. In this paper, the problems related to the behaviour of a group ... [more ▼]

A satisfactory prediction of the settlements of hyperstatic structures is becoming more and more important in their design and construction. In this paper, the problems related to the behaviour of a group of piles and to the quality of the drilled piles of the canal-bridge of Houdeng (Belgium) are analysed in a non conventional fashion, based on a finite element analysis, thanks to sufficient experimental data. The influence of an imperfectly cleaned excavation bottom and of the destructuration of the bottom rocks caused by the drilling of the piles is investigated. A particular attention is also given to the behaviour of a group of piles. [less ▲]

Detailed reference viewed: 130 (17 ULg)
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See detailModélisation : passage d'un problème réel à un problème mathématique
Bair, Jacques ULg; Haesbroeck, Gentiane ULg

in Bulletin de l'APMEP (1998), 418

Cet article présente un modèle relatif à la transformation d'un problème réel en un problème mathématique, puis du passage d'une solution mathématique à une solution réelle. Cette modélisation est ... [more ▼]

Cet article présente un modèle relatif à la transformation d'un problème réel en un problème mathématique, puis du passage d'une solution mathématique à une solution réelle. Cette modélisation est illustrée par des exemples concrets. [less ▲]

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See detailLa modélisation à l’aide du modèle SWAT des flux hydriques et du transport en suspension sur le bassin versant de la vallée de l’oued EL-Hachem
Tadrist, Nassima ULg; Debauche, Olivier ULg

in Revue des Régions Arides (2014)

Dans le Maghreb, les barrages souffrent régulièrement d’un envasement excessif lié aux problèmes d’érosion présent dans les impluviums situés en amont des barrages. Les origines de cette érosion sont ... [more ▼]

Dans le Maghreb, les barrages souffrent régulièrement d’un envasement excessif lié aux problèmes d’érosion présent dans les impluviums situés en amont des barrages. Les origines de cette érosion sont multiples : aménagement du territoire, déforestation, affectation des terres,… L’hydrologie couplée aux systèmes d’informations géographiques permet à l’aide de modèles distribués et physiquement basés de prédire l’évolution de l’envasement des barrages. L’application de ces modèles en Algérie permettra à terme, de prédire l’impact d’aménagement anti érosifs, de schémas d’aménagement du territoire sur l’envasement des barrages en estimant précisément la quantité de sédiments produit par l’érosion par ruissellement ainsi que le taux de remplissage. Une méthodologie basée sur les données cartographiques (modèle numérique de terrain, carte pédologie, carte géologie et la cartographie d’occupation du sol) ainsi que les données météorologiques journalières (température, humidité relative, vitesse du vent, radiation solaire) est en cours d’élaboration et de test sur le barrage de Bourkourdane. Cette méthodologie utilise le modèles SWAT Le modèle SWAT est utilisé pour prédire la quantité de sédiment s’accumulant dans le barrage, les flux hydriques débit entrants, sortants, ainsi que les volumes d’eau et de sédiments stockés dans le barrage. Une gestion adéquates des lâchers, couplée à une meilleure gestion de l’érosion en amont du barrage permettra d’allonger la durée de vie des barrages Algériens. Plus particulièrement pour le barrage de Boukourdane, une amélioration de la gestion des lâchers est primordiale pour améliorer la recharge de la nappe, lutter contre l’intrusion des eaux marines, et prévenir l’accumulation des particules fines qui réduisent la perméabilité du sol. [less ▲]

Detailed reference viewed: 76 (14 ULg)
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See detailModélisation architecturale pour l'évaluation de la performance énergétique
Juchmes, Roland ULg; Dawans, Arnaud ULg; Delfosse, Vincent ULg et al

in Bignon, Jean-Claude; Halin, Gilles; Kubicki, Sylvain (Eds.) Conception architecturale numérique et approches environnementales : Actes du 3ème séminaire de conception architecturale numérique (2009)

L'article présente un outil logiciel de modélisation original, développé dans le cadre de la nouvelle directive européenne sur la performance énergétique des bâtiments (PEB). Basé sur une approche ... [more ▼]

L'article présente un outil logiciel de modélisation original, développé dans le cadre de la nouvelle directive européenne sur la performance énergétique des bâtiments (PEB). Basé sur une approche "centrée utilisateur", l'outil poursuit l'objectif de faciliter la description géométrique et technologique d'un bâtiment à différents stades de son processus de conception. Le papier présente les principes et options qui sous-tendent cette application, illustre les fonctionnalités actuellement implémentées et commente une première évaluation menée avec l'appui d'un groupe d'utilisateurs. [less ▲]

Detailed reference viewed: 69 (4 ULg)
See detailModelisation biomecanique articulaire
Noble, Prisca ULg

Scientific conference (2009, July 10)

Excessive biomechanical stresses are commonly believed to be important in the pathogenesis of various osteoarticular disorders (Radin et al. 1972; Radin 1983). In order to understand better the ... [more ▼]

Excessive biomechanical stresses are commonly believed to be important in the pathogenesis of various osteoarticular disorders (Radin et al. 1972; Radin 1983). In order to understand better the constraints (friction, joint contact force) in the equine locomotor dynamics, some modelisations have been performed. This speech presents different experimental approaches (in vitro, ex vivo and in vivo) that investigated these contrainsts. [less ▲]

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See detailModélisation couplée et non linéaire de la subsidence induite par des pompages d'eau souterraines en zones d'estuaires et de deltas
Dassargues, Alain ULg

in Proceedings of the Int. Symp. on Impact of Industrial Activities on the Groundwater (1994)

Detailed reference viewed: 36 (4 ULg)