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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Simulação numérica do escoamento em difusores radiais usando o método da fronteira imersa

Lacerda, Jônatas Ferreira [UNESP] 08 September 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:23:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-09-08Bitstream added on 2014-06-13T19:09:39Z : No. of bitstreams: 1 lacerda_jf_me_ilha.pdf: 4631781 bytes, checksum: cad33ad7c5cac9de6cec08fd94b419e7 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Nesse trabalho resolve-se numericamente o escoamento em difusores radiais, os quais têm sido utilizados como modelo para o estudo do escoamento em válvulas automáticas de compressores de refrigeração. As equações governantes do escoamento, escritas no sistema de coordenadas cilíndricas, são resolvidas utilizando um código numérico baseado no Método dos Volumes Finitos. O Método da Fronteira Imersa, em conjunto com o Modelo Físico Virtual, foi implementado no código numérico e utilizado para representar a região sólida imersa no escoamento. Inicialmente, o código numérico foi utilizado para resolver o problema do escoamento em torno de um cilindro de base quadrada, como parte do processo de validação do código. O confronto dos resultados numéricos com dados da literatura indicou a validação parcial do código. Posteriormente, realizou-se um estudo preliminar do comportamento da solução do escoamento no difusor radial em relação a diversos parâmetros geométricos e de simulação numérica, com o objetivo de identificar a configuração numérica capaz de fornecer, simultaneamente, resultados satisfatórios com o menor custo computacional. Usando esta configuração, o código numérico foi validado através da comparação dos resultados da distribuição de pressão sobre o disco frontal (palheta) do difusor com dados experimentais da literatura, para duas distâncias entre disco frontal e disco inferior (assento), s=0,02 e 0,025 cm, e números de Reynolds variando entre 1500 e 2500. As comparações entre esses resultados mostraram que a metodologia utilizada é adequada para estudar o problema. Finalmente, a geometria do disco inferior foi modificada através da inserção de um chanfro com três ângulos de inclinação (30, 45 e 60º), com o objetivo de avaliar sua influência sobre o comportamento da distribuição de pressão sobre o disco frontal... / In this work the flow in radial diffusers, which have been used as a model to study the flow in refrigeration compressors valves, is solved numerically. The governing equations, written in cylindrical coordinates, are solved using a numerical code based on the Finite Volume Method. The Immersed Boundary Method, with the Virtual Physical Method, was implemented in the numerical code and used to represent the solid region immersed in the flow. Initially, the numerical code was used to solve the flow around a square base cylinder, as part of the code validation. The comparison of the numerical results with literature data indicated the partial validation of the code. Afterwards it was performed a preliminary study of the behavior of the flow solution in the radial diffuser relating to several geometrical and numerical parameters, with the objective of identifying a configuration capable of providing, simultaneously, satisfactory results with the smaller computational cost. Using this configuration, the numerical code was validated through the comparison with experimental pressure distribution on the frontal disk (reed) for two gaps between the frontal disk and inferior disk (seat), s=0.020 and 0.025 cm, and Reynolds numbers varying between 1500 and 2500. These comparisons have shown that the implemented methodology is suitable to study this problem. Finally, the inferior disk geometry was modified by inserting a chamfer with three inclination angles (30, 45 e 60º), with the objective of evaluating its influence on the pressure distribution on the frontal disk. The decreasing of the total pressure gradient through the flow for increasing inclination angles indicates less amount of energy to drive the flow. This is an important result that can be used to design refrigeration compressors with lower compression power
52

Simulação numérica do escoamento em difusores radiais usando o método da fronteira imersa /

Lacerda, Jônatas Ferreira. January 2009 (has links)
Orientador: José Luiz Gasche / Banca: Sérgio Said Mansur / Banca: Aristeu da Silveira Neto / Resumo: Nesse trabalho resolve-se numericamente o escoamento em difusores radiais, os quais têm sido utilizados como modelo para o estudo do escoamento em válvulas automáticas de compressores de refrigeração. As equações governantes do escoamento, escritas no sistema de coordenadas cilíndricas, são resolvidas utilizando um código numérico baseado no Método dos Volumes Finitos. O Método da Fronteira Imersa, em conjunto com o Modelo Físico Virtual, foi implementado no código numérico e utilizado para representar a região sólida imersa no escoamento. Inicialmente, o código numérico foi utilizado para resolver o problema do escoamento em torno de um cilindro de base quadrada, como parte do processo de validação do código. O confronto dos resultados numéricos com dados da literatura indicou a validação parcial do código. Posteriormente, realizou-se um estudo preliminar do comportamento da solução do escoamento no difusor radial em relação a diversos parâmetros geométricos e de simulação numérica, com o objetivo de identificar a configuração numérica capaz de fornecer, simultaneamente, resultados satisfatórios com o menor custo computacional. Usando esta configuração, o código numérico foi validado através da comparação dos resultados da distribuição de pressão sobre o disco frontal (palheta) do difusor com dados experimentais da literatura, para duas distâncias entre disco frontal e disco inferior (assento), s=0,02 e 0,025 cm, e números de Reynolds variando entre 1500 e 2500. As comparações entre esses resultados mostraram que a metodologia utilizada é adequada para estudar o problema. Finalmente, a geometria do disco inferior foi modificada através da inserção de um chanfro com três ângulos de inclinação (30, 45 e 60º), com o objetivo de avaliar sua influência sobre o comportamento da distribuição de pressão sobre o disco frontal... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work the flow in radial diffusers, which have been used as a model to study the flow in refrigeration compressors valves, is solved numerically. The governing equations, written in cylindrical coordinates, are solved using a numerical code based on the Finite Volume Method. The Immersed Boundary Method, with the Virtual Physical Method, was implemented in the numerical code and used to represent the solid region immersed in the flow. Initially, the numerical code was used to solve the flow around a square base cylinder, as part of the code validation. The comparison of the numerical results with literature data indicated the partial validation of the code. Afterwards it was performed a preliminary study of the behavior of the flow solution in the radial diffuser relating to several geometrical and numerical parameters, with the objective of identifying a configuration capable of providing, simultaneously, satisfactory results with the smaller computational cost. Using this configuration, the numerical code was validated through the comparison with experimental pressure distribution on the frontal disk (reed) for two gaps between the frontal disk and inferior disk (seat), s=0.020 and 0.025 cm, and Reynolds numbers varying between 1500 and 2500. These comparisons have shown that the implemented methodology is suitable to study this problem. Finally, the inferior disk geometry was modified by inserting a chamfer with three inclination angles (30, 45 e 60º), with the objective of evaluating its influence on the pressure distribution on the frontal disk. The decreasing of the total pressure gradient through the flow for increasing inclination angles indicates less amount of energy to drive the flow. This is an important result that can be used to design refrigeration compressors with lower compression power / Mestre
53

Écoulements lors d'inondations en milieu urbain : influence de la topographie détaillée et des échanges avec le réseau d'assainissement / Flows during floods in urban areas : influence of the detailed topography and exchanges with the sewer system

Bazin, Pierre-Henri 05 December 2013 (has links)
Le but de cette thèse est d'étudier la modélisation détaillée des écoulements qui ont lieu lors des inondations urbaines. Dans une première partie, des écoulements en bifurcation incluant des petits obstacles génériques ou des profils de canaux avec trottoirs sont étudiés sur une maquette expérimentale, puis simulés numériquement avec le modèle bidimensionnel Rubar20. Les résultats expérimentaux et numériques montrent l'avantage d'inclure des obstacles de petite taille dans un modèle d'inondation urbaine, alors qu'il n'y a qu'un intérêt limité à utiliser une topographie détaillée des rues. Dans une deuxième partie, les interactions entre écoulements de surface et écoulements en conduites souterraines sont étudiées. Un modèle physique de système de drainage urbain permet de valider un modèle analytique prédisant les débits d'échange entre les deux couches d'écoulement. Une modélisation 1D/2D (conduite/rue) est mise en place avec les modèles Rubar3/Rubar20 et validée sur des écoulements expérimentaux observés sur le modèle physique. Dans une troisième partie, les inondations dans la ville d'Oullins (près de Lyon, France) sont étudiées. La modélisation des écoulements de surface est validée avec des données de terrain, et nous discutons l'intérêt de plusieurs représentations du milieu urbain. L'intégration du réseau d'assainissement dans un modèle 1D/2D reste affectée par plusieurs incertitudes, mais cette étape montre l'intérêt de la modélisation couplée pour décrire les interactions complexes des écoulements lors d'inondations urbaines, ainsi que les limites de l'approche développée pour les écoulements à faible profondeur / Aim of this thesis is to study the detailed modelling of flows that occur during urban floods. In a first part, bifurcation flows including small obstacles or channel profiles with sidewalks are studied on an experimental facility, and then numerically simulated with the two dimensional model Rubar20. Experimental and numerical results show the benefits of including small obstacles in an urban flood model, whereas there is only little benefit of using a detailed representation of the streets topography. In a second part, interactions between surface and underground pipe flows are studied. A physical model of an urban drainage system allows the validation of an analytical model predicting exchange discharges between both flow layers. A 1D/2D modelling (pipe/street) is set up with the models Rubar3/Rubar20 and validated on experimental flows observed on the physical model. In a third part, floods in the city of Oullins (near Lyon, France) are studied. Surface flows modelling is validated with field data, and we discuss the interest of several representations of the urban area. Integration of the sewer system in a 1D/2D model remains impacted by several uncertainties, yet this step shows the interest of the coupled modelling to describe complex flows interactions during urban floods, as well as limitations of the developed approach for shallow flows
54

On the hydro-mechanical behavior of ancient railway flatforms in term of reinforcement by soil-mixing / Étude du comportement hydromécanique des plateformes ferroviaires anciennes en vue du renforcement par le 'soil-mixing'

Duong, Trong Vinh 25 November 2013 (has links)
Le présent travail porte sur le comportement des plates-formes ferroviaires anciennes en France. Tout d'abord, une étude statistique a été menée sur les problèmes survenus dans l'ensemble du réseau ferroviaire français. L'analyse montre l'importance particulière de la qualité du sol support pour la performance de la sous-structure et pour la tenue géométrique des voies. Ensuite, une ligne ferroviaire ancienne située à l'Ouest de la France a été étudiée spécifiquement. Les analyses montrent que la vitesse de dégradation de cette ligne est en corrélation avec les différents paramètres tels que la nature de sol support, l'épaisseur des couches de la sous-structure. Une tendance d'augmentation de la vitesse de dégradation avec la diminution de l'épaisseur de la couche intermédiaire est identifiée. Cette couche as un impact positif puisqu'elle réduit les contraintes appliquées au sol support. Le comportement hydromécanique du sol de la couche intermédiaire dans des conditions différentes (teneur en eau, teneur en particules fines, charge, nombre de cycles) a été étudié. Des essais triaxiaux et des essais de colonne d'infiltration ont été réalisés à cette fin. En analysant les propriétés de résistance au cisaillement, la déformation axiale permanente et le module réversible, on a constaté que les effets de la teneur en eau et de la teneur en fines doivent être pris en compte ensemble. Une augmentation de teneur en fines dans la couche intermédiaire présente un impact positif à l'état non saturé grâce à l'effet de la succion, mais un impact négatif à l'état saturé. Les essais de colonne d'infiltration avec des cycles de séchage/humidification ont montré que la conductivité hydraulique du sol est gouvernée par la fraction de fines et qu'elle ne change pas significativement avec la teneur en fines. Afin d'étudier les mécanismes de la création de la couche intermédiaire et de remontée boueuse, un modèle physique de 550 mm de diamètre intérieur a été développé. Des échantillons de sol qui représentent la sous-structure ferroviaire ancienne avec une couche de ballast posée sur une couche de limon artificielle (mélange de sable concassé et du kaolin) ont été testés. Les effets des charges monotones et cycliques, de la teneur en eau et de la masse volumique sèche du sol support ont été étudiés. Il a été constaté que la pression interstitielle développée dans le sol support et la rigidité du sol support sont des facteurs clés pour la migration des particules fines ou la création de la couche intermédiaire/la remontée boueuse. L'eau est la condition nécessaire, mais c'est la compressibilité du sol support qui gouverne le phénomène à se produire / The present work deals with the behavior of ancient railway sub-structure in France. A statistical study was firstly undertaken on problems occurred in the whole ancient French railway network. The analysis evidenced the particular importance of sub-grade quality for the performance of the sub-structure and the track geometry. Afterwards, an ancient railway line in the West of France was investigated. The analysis showed that the degradation speed of this line was correlated with different parameters such as the nature of sub-grades and the thickness of different layers. An increase trend of degradation speed with the increase in interlayer thickness was identified. The interlayer has a positive impact since it reduces the train-induced stress applied to the sub-grade. The hydro-mechanical behavior of interlayer soil under different conditions (water content, fines content, stress, number of cycles) was investigated. A set of triaxial tests and infiltration tests were performed for this purpose. By analyzing the shear strength properties, the permanent axial strain and the resilient modulus of interlayer soil, we found that the water content and the fines content must be considered together. Adding more fines into the interlayer presents a positive impact under unsaturated conditions thanks to the suction effect, but a negative impact under saturated conditions. The infiltration column tests with drying/wetting cycles showed that the hydraulic conductivity of interlayer soil is governed by fines fraction but did not change significantly with fines content. In order to study the mechanism of interlayer creation and mud pumping, a physical model of 550 mm inner diameter was developed. Soil samples representing the ancient French railway substructure with a ballast layer overlying an artificial silt layer (mixture of crushed sand and kaolin were tested. The effects of monotonic and cyclic loadings, water content and dry unit mass of sub-soil were investigated. It was found that the pore water pressure developed in the sub-soil and the sub-soil stiffness are the key factors for the migration of fine particles or the creation of interlayer/mud pumping. Water is the necessary condition, but it is the soil compressibility that governs the phenomenon to occur
55

Numerické modelování proudění v bezpečnostním objektu vodního díla / Numerical Modelling of Flow over Spillway

Holinka, Matouš January 2017 (has links)
This thesis deals with the solution of numerical modeling. Consequently problems associated with the flow of the water over spillway of the specific water structure. In this case numerical modeling means modeling of fluid movement, which is described by mathematical means. Especially nowadays, when a lot of spillways need to be recalculated, whether it meets the capacity demands, or there is no need to tackle reconstruction. With today's software capabilities there is a wide range of commercial and freeware resources. The numerical model, compared to physical model is less accurate which is, on the otherhand, physical model is usually financially and time-consuming. The following work simulates the behavior of water on the edge of the spillway, in the trough and then behind the trough. The result is a comparison of the water depth in the trough calculated by the numerical and the physical model.
56

Advancing the use of geographic information systems, numerical and physical models for the planning of managed aquifer recharge schemes

Sallwey, Jana 12 November 2020 (has links)
Global change is a major threat to local groundwater resources. Climate change and population growth are factors that directly or indirectly augment the increasing uptake of groundwater resources. To outbalance the pressure on aquifers, managed aquifer recharge (MAR) schemes are increasingly being implemented. They enable the subsurface storage of surplus water for times of high demand. The complexity of MAR schemes makes their planning and implementation multifaceted and requires a comprehensive assessment of the local hydrogeological and hydrogeochemical conditions. Despite the fact that MAR is a widely used technique, its implementation is not well regulated and comprehensive planning and design guidelines are rare. The use of supporting tools, such as numerical and physical models or geographic information systems (GIS), is rising for MAR planning but their scope and requirements for application are rarely reflected in the available MAR guidelines. To depict the application potential and the advantages and disadvantages of the tools for surface infiltration MAR planning, this thesis comprises reviews on the past use of the tools as well as suggestions to improve their applicability for MAR planning. GIS is not mentioned by most MAR guidelines as a planning tool even though it is increasingly being used for MAR mapping. Through a review of GIS-based MAR suitability studies, this thesis shows that the MAR mapping process could be standardized by using the often-applied approach of constraint mapping, suitability mapping by using pairwise comparison for weight assignment and weighted linear combination as a decision rule, and a subsequent sensitivity analysis. Standardizing the methodology would increase the reliability and comparability of MAR maps due to the common methodological approach. Thus, the proposed standard methodology was incorporated into a web GIS that simplifies MAR mapping through a pre-defined workflow. Numerical models are widely used for the assessment of MAR schemes and are included into some MAR planning guidelines. However, only a few studies were found that utilized vadose zone models for the planning and design of MAR schemes. In this thesis, a review and a subsequent case study highlight that numerical modelling has many assets, such as monitoring network design or infiltration scenario planning, that make its utilization during the MAR planning phase worthwhile. Consequently, this study advocates the use of vadose zone models for MAR planning by showing their potential areas of application as well as their uncertainties that need to be regarded carefully during modelling. Physical models used for MAR planning are typically field or pilot sites, as some MAR legislation requests pilot sites as part of the preliminary assessment. Laboratory experiments are used less often and are mostly restricted to the analysis of very specific issues, such as clogging. This thesis takes on the issue of scaling laboratory results to the field scale by comparing results from three physical models of different scales and dimensionality. The results indicate that preferential flow paths, air entrapment and boundary influence limit the quantitative validity of laboratory experiments. The use of 3D tanks instead of 1D soil columns and the application of statistical indicators are means to increase the representativeness of laboratory measurements. Nevertheless, physical models have the potential to improve MAR planning in terms of detailed process assessment, scenario and sensitivity analyses. All tools discussed in this thesis have their merits for MAR scheme planning and should be advocated better in MAR guidelines by depicting their application potential, advantages and disadvantages. The information accumulated in this thesis is a step towards an advanced use of supporting tools for the planning and design of MAR schemes.:1 Introduction 1.1 Motivation 1.2 Objectives 1.3 Structure of the thesis 2 Status quo of the planning process of MAR schemes 2.1 Guidance documents on general MAR planning 2.2 Application of GIS, numerical and physical models for MAR planning 2.3 Planning of surface infiltration schemes 3 Using GIS for the planning of MAR schemes 3.1 Implications from GIS-MCDA studies for MAR mapping 3.2 Development of web tools for MAR suitability mapping 4 Using numerical models for the planning of MAR schemes 4.1 Review on the use of numerical models for the design and optimization of MAR schemes 4.2 Planning a small-scale MAR scheme through vadose zone modelling 5 Using physical models for the planning of MAR schemes 5.1 Design of the experimental study 5.2 Comparison of three different physical models for MAR planning 6 Discussion and research perspectives 7 Bibliography 8 Appendix / Der globale Wandel stellt eine große Bedrohung für die lokalen Grundwasserressourcen dar. Klimawandel und Bevölkerungswachstum sind Faktoren, die, direkt oder indirekt, die zunehmende Nutzung von Grundwasserressourcen verstärken. Um diesen Druck auf die Grundwasserleiter auszugleichen, werden verstärkt Maßnahmen zur gezielten Grundwasserneubildung (managed aquifer recharge = MAR) durchgeführt. Dies ermöglicht die unterirdische Speicherung von überschüssigem Wasser für Zeiten hohen Bedarfs. Die Komplexität von MAR-Anlagen macht ihre Planung und Umsetzung kompliziert und erfordert eine umfassende Bewertung der lokalen hydrogeologischen und hydrogeochemischen Bedingungen. Trotz der weltweiten Implementierung von MAR ist dessen Planung wenig reguliert. Umfassende Planungs- und Gestaltungsrichtlinien sind rar. Der Einsatz unterstützender Werkzeuge, wie numerischer und physikalischer Modelle oder Geoinformationssysteme (GIS), nimmt bei der MAR-Planung zu, aber ihre Einsatzmöglichkeiten und ihre Anforderungen an die Anwendung spiegeln sich selten in den verfügbaren MAR-Richtlinien wider. Um das Anwendungspotential und die Vor- und Nachteile der Werkzeuge für die MAR-Planung darzustellen, wurden für diese Arbeit Recherchen über den bisherigen Einsatz der Werkzeuge durchgeführt. Zusätzlich wurden Vorschläge zur Erhöhung ihrer Anwendbarkeit für die MAR Planung gemacht. Der Schwerpunkt lag dabei auf Oberflächeninfiltrationsverfahren. GIS wird in keiner MAR-Richtlinie als Planungsinstrument erwähnt, obwohl es zunehmend für die MAR-Kartierung eingesetzt wird. Eine Recherche über GIS-basierte MAR-Eignungsstudien zeigte, dass der MAR-Kartierungsprozess standardisiert werden kann mittels des oft genutzten Ansatzes: initiales Ausschneiden von Gebieten, welche Restriktionen unterliegen, dem folgend die Eignungskartierung mittels Paarvergleich für die Wichtung der GIS-Karten und der gewichteten Linearkombination als Entscheidungsregel, sowie eine abschließende Sensitivitätsanalyse. Die Standardisierung der Methodik könnte die Zuverlässigkeit und Vergleichbarkeit von MAR-Karten aufgrund des gemeinsamen methodischen Ansatzes erhöhen. Daher wurde die standardisierte Methodik in ein Web-GIS integriert, das über einen definierten Workflow die MAR-Kartierung vereinfacht. Numerische Modelle werden häufig für die Beurteilung von MAR-Systemen verwendet und sind in einigen MAR-Planungsrichtlinien ausgewiesen. Es wurden jedoch nur wenige Studien gefunden, die die Modelle der ungesättigten Zone für die Planung und Gestaltung von MAR Standorten verwendeten. Die in dieser Arbeit durchgeführte Literaturrecherche und eine darauf aufbauende Fallstudie zeigen, dass die numerische Modellierung viele Vorteile bietet, wie z. B. beim Design eines Monitoring-Netzwerkes oder bei der Planung von Infiltrationsszenarien. Physikalische Modelle, die für die MAR-Planung verwendet werden, sind meist Feld- oder Pilotversuche, da einige MAR-Gesetzgebungen Pilotstandorte im Rahmen der Vorabbewertung verlangen. Laborexperimente werden seltener eingesetzt und beschränken sich meist auf die Analyse sehr spezifischer Fragestellungen, wie z.B. der Kolmatierung. Diese Arbeit beschäftigt sich mit der Skalierbarkeit von Laborergebnissen auf die Feldskale, indem sie Ergebnisse aus drei physikalischen Modellen verschiedener Maßstäbe und Dimensionen vergleicht. Die Ergebnisse deuten darauf hin, dass Makroporen, Lufteinschlüsse und der Einfluss der Randbedingungen die quantitative Aussagekraft von Laborversuchen einschränken. Der Einsatz von 3D-Tanks anstelle von 1D-Bodensäulen oder von statistischen Indikatoren ist ein Mittel zur Erhöhung der Repräsentativität von Labormessungen. Nichtsdestotrotz hat die Anwendung physikalischerModelle das Potenzial, die MAR-Planung in Bezug auf detaillierte Prozessbewertung, Szenarien und Sensitivitätsanalysen zu unterstützen. Alle beschriebenen Instrumente haben ihre Vorzüge bei der Bewertung von MAR-Anlagen und sollten in MAR-Richtlinien detaillierter berücksichtigt werden, indem ihr Anwendungspotenzial, ihre Vor- und ihre Nachteile dargestellt werden. Die für diese Arbeit zusammengestellten Informationen sind ein Schritt zur Förderung der beschriebenen Planungsinstrumente für die Planung und Gestaltung von MAR-Anlagen.:1 Introduction 1.1 Motivation 1.2 Objectives 1.3 Structure of the thesis 2 Status quo of the planning process of MAR schemes 2.1 Guidance documents on general MAR planning 2.2 Application of GIS, numerical and physical models for MAR planning 2.3 Planning of surface infiltration schemes 3 Using GIS for the planning of MAR schemes 3.1 Implications from GIS-MCDA studies for MAR mapping 3.2 Development of web tools for MAR suitability mapping 4 Using numerical models for the planning of MAR schemes 4.1 Review on the use of numerical models for the design and optimization of MAR schemes 4.2 Planning a small-scale MAR scheme through vadose zone modelling 5 Using physical models for the planning of MAR schemes 5.1 Design of the experimental study 5.2 Comparison of three different physical models for MAR planning 6 Discussion and research perspectives 7 Bibliography 8 Appendix
57

Physical and numerical modelling investigation of induced bank erosion as a sediment transport restoration strategy for trained rivers : the case of the Old Rhine (France) / Rétablissement de la dynamique sédimentaire dans les cours d'eau aménagés par érosion induite des berges : modélisation physique et numérique, cas du Vieux-Rhin

Die Moran, Andrés 19 December 2012 (has links)
La dynamique sédimentaire des rivières, souvent modifiée par les aménagements, n'a pas été considérée comme un facteur significatif pour la qualité des environnements riverains et dans les stratégies de restauration. Les approches destinées à restaurer la charge sédimentaire d'une rivière afin qu'elle soit compatible avec les besoins environnementaux et humains, en termes de quantité de sédiments et de granulométrie, sont encore peu développées. De plus, les approches existantes telles que l'injection de sédiments sont souvent coûteuses et nécessitent une intervention humaine. Cette thèse porte sur l'érosion induite des berges, qui constitue une alternative plus durable pour l'environnement. Cette approche consiste à accroître le potentiel d'érosion en certains sites le long des berges d'une rivière chenalisée, en leur permettant d'être plus fortement érodés lors de crues. Deux approches, un modèle physique et des simulations numériques, ont été utilisées pour étudier un site localisé sur le Vieux-Rhin, en aval de Bâle (Suisse), où une modification des épis éxistents est prévue afin de favoriser l'érosion des berges. Dans un premier temps, différents scénarios de modification ont été testés sur une gamme de débits, au moyen d'un modèle physique à échelle de Froude non distordue avec un lit mobile. Dans ce modèle physique, un mélange de quatre classes granulométriques a été adopté afin de reproduire la courbe granulométrique mesurée en nature. Le modèle a été mis à l'échelle par une méthode spécifique qui représente avec précision le début du mouvement de chaque classe. Une stratégie efficace d'érosion des berges a été établie, qui libère des sédiments sans provoquer un retrait excessif des berges qui puisse compromettre la sécurité d'un chenal de navigation adjacent. Par la suite, l'aptitude du modèle numérique Telemac2D à modéliser l'érosion et les processus de rupture de berge a été évaluée. L'algorithme existant de rupture de berge a été modifié pour améliorer les résultats, et les développements implémentés ont été validés par des comparaisons sur des cas-tests de laboratoire. Enfin, les essais du modèle physique ont été simulés numériquement à la même échelle. Les simulations reproduisent les processus observés sur le modèle physique, et les volumes de sédiments érodés et déposés sont du même ordre de grandeur que ceux mesurés / Sediment transport dynamics, often heavily modified by river training, are not yet sufficiently considered as a significant factor in riparian environmental quality and river restoration strategies. Approaches for restoring a river's sediment in quantity and in grain size distribution, so that it is compatible with both ecological and human needs, are still under development. Furthermore, existing approaches such as direct sediment injection are often expensive and require human intervention. This thesis explores induced bank erosion, a more environmentally sustainable alternative. This approach involves increasing the potential for erosion at certain sites along the bank of a trained river, and allowing them to be eroded during high flow periods. Two modelling approaches, physical scaled models and numerical simulation, were used to study a site located on the Old Rhine downstream of Basle (Switzerland) where existing bank protection groynes will be modified to induce bank erosion. Firstly, different modification options were tested over a range of flow rates with a Froude-scaled undistorted movable-bed physical model. The physical model used a mixture of four grain sizes to reproduce the bank grain size distribution found at the site, and was scaled according to a specific method which accurately represents initiation of motion for each grain size. An effective bank erosion strategy was found that releases sediment without compromising the safety of an adjacent navigation channel through excessive bank retreat. Subsequently, the capability of the Telemac2D two-dimensional depth-averaged numerical modelling system to model bank erosion and failure processes was assessed, and the existing bank failure algorithm was modified in order to improve results. Algorithm developments were tested with two laboratory test cases. Then, the physical model tests were simulated at their same scale. Simulations reproduced the processes present in the physical model tests, and volumes of eroded and deposited sediment were of the same order of magnitude
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Perspectiva histórica e tecnológica da calibração do túnel 2 do Sistema Cantareira de adução de água para a região metropolitana de São Paulo / Historical and technological perspective of the test for the calibration of tunnel 2 of the Cantareira water project for the metropolitan area of São Paulo

Pinheiro, Hemerson Donizete 22 March 2007 (has links)
Trabalhos de cunho historiográfco que visam resgatar a produção científica e tecnológica de um país tem auxiliado a compreender e a classificar seu nível de desenvolvimento frente a estas questões. Com este trabalho, espera-se dar início no Departamento de Hidráulica e Saneamento (SHS) da Escola de Engenharia de São Carlos, a um levantamento historiográfico da produção tecnológica e científica de seus pós-graduandos e professores. Para tanto, resgata-se um trabalho realizado entre o final da década de 1960 e início da década de 1970, pela Cátedra de Mecânica dos Fluidos (precursora do SHS), que teve como objetivo prever a vazão de água do túnel 2 do Sistema Cantareira de abastecimento de água para a região metropolitana de São Paulo. Nesta galeria foi realizado um ensaio original com circulação de ar, para o qual foram desenvolvidos métodos e técnicas a fim de verificar a vazão e auxiliar no seu dimensionamento, para garantir uma adução de 33 \'M POT.3\'/s. Mediante o levantamento, organização cronológica e análise dos documentos produzidos pelos autores do referido ensaio, resgatam-se as influências teóricas que nortearam as metodologias, as técnicas e tecnologias e analisam-se, de acordo com os registros documentais, a execução e resultados alcançados pelos ensaios. / Works that have as objective to review the scientific and technological production of a country have helped to understand and to measure its level of development regarding these questions. With this work, hopefully a historical survey of the technological and scientific production of its graduate students and teachers begins at the Departamento de Hidráulica e Saneamento (SHS) at the Escola de Engenharia de São Carlos. In this way, a work that was carried out between the end of the 1960\'s and beginning of the 1970\'s, by the chair of fluid mechanics (precursor of the SHS), which had as objective to foresee the water flow rate at tunnel 2 of the Cantareira water project for the metropolitan area of São Paulo. An original test using air circulation was carried out in the tunnel. Methods and techniques were developed in order to verify the flow rate and check its size, to guarantee 33 \'M POT.3\'/s of flow. The documents produced by the authors of the test were surveyed, organized chronologically and analyzed, seeking to infer the theoretical influences that had guided the methodologies, to describe the techniques and technologies and to analyze, in accordance with the document registers, the execution and results reached from the tests.
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Customização em massa de projeto de habitação de interesse social por meio de modelos físicos paramétricos / Mass customization of social housing project through parametric physical models

Mauricio Hidemi Azuma 08 March 2016 (has links)
Esta pesquisa aborda como problema principal, a falta de participação do usuário de Habitação de Interesse Social (HIS) na definição da sua moradia. O modelo atual do processo de provisão da habitação é baseado, principalmente, no sistema de produção em massa, resultando em unidades habitacionais padronizadas que não atendem às necessidades de seus usuários. Dentro deste cenário, a Customização em Massa (CM), tem sido investigada e apontada como uma estratégia promissora para solucionar este problema. A CM é definida como uma síntese de dois sistemas, aparentemente concorrentes: o da produção em massa com a customização individual de bens ou serviços. A participação do cliente na configuração do seu produto é uma condição essencial no conceito da CM, para o atendimento de suas necessidades e desejos. Para viabilizar essa participação, é necessária a utilização de ferramentas que permitam aos clientes configurarem seus produtos, a partir de opções disponibilizadas pelo fabricante. Especificamente no setor da construção civil, estas ferramentas ainda precisam ser desenvolvidas e experimentadas. Neste contexto, o objetivo principal da pesquisa é desenvolver um instrumento funcional que apoie os usuários, nas decisões da customização da sua habitação, em processos participativos de projetos de HIS. A pesquisa utiliza a abordagem da Design Science Research, a qual orienta para que, após a compreensão da questão central, seja proposto um artefato aplicável em soluções práticas. Os resultados obtidos com a aplicação do artefato desenvolvido demonstraram que o mesmo pode ser utilizado, não apenas na CM, mas também em outros processos de projetos participativos. A principal contribuição desta pesquisa está na originalidade das características paramétricas do modelo físico proposto. / This research approaches, as a main problem, the lack of user participation in Social Housing regarding the definition of its dwelling. The current model of housing provision process is based, mainly, on the mass production system, resulting in standardized housing units that do not satisfy the needs of users. Within this background, the Mass Customization (MC), has been investigated and identified as a promising strategy to solve this problem. The MC is defined as a synthesis of two systems, seemingly competitive: the mass production with the individual customization of goods or services. The customer participation in his product configuration is an essential condition in the concept of MC to fulfill his needs and desires. In order to enable this participation, the use of tools is required to enable customers to configure their products, from options, provided by the manufacturer. Specifically, in the civil construction sector these tools still need to be developed and experienced. In this context, the main objective of this research is the development of a functional device that can support users in their decisions of housing customization in participatory processes of Social Housing projects. The research uses the Design Science Research approach, which after understanding the central issue, recommends the development of an artifact and its application in practical solutions. The results obtained by applying the developed artifact demonstrated that the latter can be used, not only in MC, but also in other participatory design processes. The main contribution of this research is the originality of the parametric features of the proposed physical model.
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Customização em massa de projeto de habitação de interesse social por meio de modelos físicos paramétricos / Mass customization of social housing project through parametric physical models

Azuma, Mauricio Hidemi 08 March 2016 (has links)
Esta pesquisa aborda como problema principal, a falta de participação do usuário de Habitação de Interesse Social (HIS) na definição da sua moradia. O modelo atual do processo de provisão da habitação é baseado, principalmente, no sistema de produção em massa, resultando em unidades habitacionais padronizadas que não atendem às necessidades de seus usuários. Dentro deste cenário, a Customização em Massa (CM), tem sido investigada e apontada como uma estratégia promissora para solucionar este problema. A CM é definida como uma síntese de dois sistemas, aparentemente concorrentes: o da produção em massa com a customização individual de bens ou serviços. A participação do cliente na configuração do seu produto é uma condição essencial no conceito da CM, para o atendimento de suas necessidades e desejos. Para viabilizar essa participação, é necessária a utilização de ferramentas que permitam aos clientes configurarem seus produtos, a partir de opções disponibilizadas pelo fabricante. Especificamente no setor da construção civil, estas ferramentas ainda precisam ser desenvolvidas e experimentadas. Neste contexto, o objetivo principal da pesquisa é desenvolver um instrumento funcional que apoie os usuários, nas decisões da customização da sua habitação, em processos participativos de projetos de HIS. A pesquisa utiliza a abordagem da Design Science Research, a qual orienta para que, após a compreensão da questão central, seja proposto um artefato aplicável em soluções práticas. Os resultados obtidos com a aplicação do artefato desenvolvido demonstraram que o mesmo pode ser utilizado, não apenas na CM, mas também em outros processos de projetos participativos. A principal contribuição desta pesquisa está na originalidade das características paramétricas do modelo físico proposto. / This research approaches, as a main problem, the lack of user participation in Social Housing regarding the definition of its dwelling. The current model of housing provision process is based, mainly, on the mass production system, resulting in standardized housing units that do not satisfy the needs of users. Within this background, the Mass Customization (MC), has been investigated and identified as a promising strategy to solve this problem. The MC is defined as a synthesis of two systems, seemingly competitive: the mass production with the individual customization of goods or services. The customer participation in his product configuration is an essential condition in the concept of MC to fulfill his needs and desires. In order to enable this participation, the use of tools is required to enable customers to configure their products, from options, provided by the manufacturer. Specifically, in the civil construction sector these tools still need to be developed and experienced. In this context, the main objective of this research is the development of a functional device that can support users in their decisions of housing customization in participatory processes of Social Housing projects. The research uses the Design Science Research approach, which after understanding the central issue, recommends the development of an artifact and its application in practical solutions. The results obtained by applying the developed artifact demonstrated that the latter can be used, not only in MC, but also in other participatory design processes. The main contribution of this research is the originality of the parametric features of the proposed physical model.

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