Download or read book Etude et mod les effectifs d coulements quasi 2D written by Alban Pothérat and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les ecoulements confines soumis a un fort champ magnetique vertical et les ecoulements en rotation autour d'un axe vertical presentent au moins deux caracteristiques communes marquantes : d'une part, le champ de vitesse est quasi-bidimensionnel loin des parois, et d'autre part, une couche limite de structure simple se developpe le long des parois perpendiculaires a la direction du champ magnetique (couche de hartmann) ou a l'axe de rotation (couche d'ekman). Nous presentons ici une etude de ces proprietes remarquables dans des cas ou les autres forces qui agissent sur l'ecoulement (inertie, viscosite,) ne sont plus negligeables devant la force de laplace ou de coriolis. Il est montre que la combinaison des couplages verticaux et horizontaux conduit d'une part, a une dependance quadratique du champ de vitesse en fonction de la verticale (effet tonneau), et d'autre part a la presence de jet dans les couches de hartmann ou d'ekman. Une loi de paroi analytique pour diverses configurations des couches de hartmann est construite (presence d'effets inertiels, presence d'une composante horizontale du champ magnetique, parois conductrices) dans le but d'eviter le maillage fin que requiert le calcul numerique direct d'une telle couche. Les proprietes remarquables des ecoulements quasi-2d sont ensuite utilisees pour construire trois modeles 2d differents, a partir de la moyenne verticale des equations du mouvement. Ces modeles simples, ne reposent que sur les hypotheses physiques et ne necessitent en particulier aucun etalonnage numerique. Le modele psm2000 pour les ecoulements mhdisavec inertie et sous fort champ vertical conduit a des resultats tres proches de l'experience et met notamment en evidence le fait que le pompage d'ekman dans les couches de hartmann se traduit approximativement par une diffusion du champ de vorticite le long des lignes de courant de l'ecoulement moyen. Un modele analogue, mais sans effets inertiels et avec un champ non homogene et instationnaire permet en premier lieu de determiner dans quel cas les couches de hartmann controlent l'ecoulement global et en second lieu, d'etudier la possibilite de controler un ecoulement d'acier liquide par un champ glissant dans un procede de coulee continue. Finalement, un modele quasi-geostrophique modifie fournit une base theorique pour l'etude du comportement des couches paralleles lors des experiences de spin-up et spin-down d'une cuve tournante.
Download or read book ETUDE ET MODELES EFFECTIFS D ECOULEMENTS QUASI 2D written by ALBAN.. POTHERAT and published by . This book was released on 2000 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt: LES ECOULEMENTS CONFINES SOUMIS A UN FORT CHAMP MAGNETIQUE VERTICAL ET LES ECOULEMENTS EN ROTATION AUTOUR D'UN AXE VERTICAL PRESENTENT AU MOINS DEUX CARACTERISTIQUES COMMUNES MARQUANTES : D'UNE PART, LE CHAMP DE VITESSE EST QUASI-BIDIMENSIONNEL LOIN DES PAROIS, ET D'AUTRE PART, UNE COUCHE LIMITE DE STRUCTURE SIMPLE SE DEVELOPPE LE LONG DES PAROIS PERPENDICULAIRES A LA DIRECTION DU CHAMP MAGNETIQUE (COUCHE DE HARTMANN) OU A L'AXE DE ROTATION (COUCHE D'EKMAN). NOUS PRESENTONS ICI UNE ETUDE DE CES PROPRIETES REMARQUABLES DANS DES CAS OU LES AUTRES FORCES QUI AGISSENT SUR L'ECOULEMENT (INERTIE, VISCOSITE,) NE SONT PLUS NEGLIGEABLES DEVANT LA FORCE DE LAPLACE OU DE CORIOLIS. IL EST MONTRE QUE LA COMBINAISON DES COUPLAGES VERTICAUX ET HORIZONTAUX CONDUIT D'UNE PART, A UNE DEPENDANCE QUADRATIQUE DU CHAMP DE VITESSE EN FONCTION DE LA VERTICALE (EFFET TONNEAU), ET D'AUTRE PART A LA PRESENCE DE JET DANS LES COUCHES DE HARTMANN OU D'EKMAN. UNE LOI DE PAROI ANALYTIQUE POUR DIVERSES CONFIGURATIONS DES COUCHES DE HARTMANN EST CONSTRUITE (PRESENCE D'EFFETS INERTIELS, PRESENCE D'UNE COMPOSANTE HORIZONTALE DU CHAMP MAGNETIQUE, PAROIS CONDUCTRICES) DANS LE BUT D'EVITER LE MAILLAGE FIN QUE REQUIERT LE CALCUL NUMERIQUE DIRECT D'UNE TELLE COUCHE. LES PROPRIETES REMARQUABLES DES ECOULEMENTS QUASI-2D SONT ENSUITE UTILISEES POUR CONSTRUIRE TROIS MODELES 2D DIFFERENTS, A PARTIR DE LA MOYENNE VERTICALE DES EQUATIONS DU MOUVEMENT. CES MODELES SIMPLES, NE REPOSENT QUE SUR LES HYPOTHESES PHYSIQUES ET NE NECESSITENT EN PARTICULIER AUCUN ETALONNAGE NUMERIQUE. LE MODELE PSM2000 POUR LES ECOULEMENTS MHDISAVEC INERTIE ET SOUS FORT CHAMP VERTICAL CONDUIT A DES RESULTATS TRES PROCHES DE L'EXPERIENCE ET MET NOTAMMENT EN EVIDENCE LE FAIT QUE LE POMPAGE D'EKMAN DANS LES COUCHES DE HARTMANN SE TRADUIT APPROXIMATIVEMENT PAR UNE DIFFUSION DU CHAMP DE VORTICITE LE LONG DES LIGNES DE COURANT DE L'ECOULEMENT MOYEN. UN MODELE ANALOGUE, MAIS SANS EFFETS INERTIELS ET AVEC UN CHAMP NON HOMOGENE ET INSTATIONNAIRE PERMET EN PREMIER LIEU DE DETERMINER DANS QUEL CAS LES COUCHES DE HARTMANN CONTROLENT L'ECOULEMENT GLOBAL ET EN SECOND LIEU, D'ETUDIER LA POSSIBILITE DE CONTROLER UN ECOULEMENT D'ACIER LIQUIDE PAR UN CHAMP GLISSANT DANS UN PROCEDE DE COULEE CONTINUE. FINALEMENT, UN MODELE QUASI-GEOSTROPHIQUE MODIFIE FOURNIT UNE BASE THEORIQUE POUR L'ETUDE DU COMPORTEMENT DES COUCHES PARALLELES LORS DES EXPERIENCES DE SPIN-UP ET SPIN-DOWN D'UNE CUVE TOURNANTE.
Download or read book Analyse num rique de mod les d coulements quasi newtoniens written by Khalid Najib and published by . This book was released on 1988 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Etude théorique et numérique du modèle de Carreau et du modèle de Bingham modifié. Existence et unicité de la solution du problème. Approximation par des méthodes d'éléments finis mixtes.
Download or read book SIMULATION DES GRANDES ECHELLES SGE D ECOULEMENTS DE FLUIDES QUASI INCOMPRESSIBLES written by JEAN-CHRISTOPHE.. MAGNIENT and published by . This book was released on 2001 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: DANS LE CADRE DE LA SIMULATION DES GRANDES ECHELLES EN MECANIQUE DES FLUIDES, LE TRAVAIL REALISE AU COURS DE CETTE THESE A POUR OBJECTIF LA MISE AU POINT DE MODELES DE TURBULENCE ADAPTES AUX SITUATIONS COMPLEXES POUR LES NOMBRES DE REYNOLDS ELEVES, ET L'EXTENSION DES MODELES BASES SUR LE CONCEPT DE FILTRAGE SPATIAL. AFIN DE S'AFFRANCHIR DES CONTRAINTES A PARTIR DESQUELLES SONT DEVELOPPEES LES MODELES CLASSIQUES (HOMOGENEITE, ISOTROPIE ET EQUILIBRE LOCAL), UNE STRATEGIE CONSISTE A PRENDRE EN COMPTE PLUS DE PHENOMENES PHYSIQUES PAR L'ADDITION DE VARIABLES ET D'EQUATIONS D'EVOLUTION. DANS UN PREMIER TEMPS, NOUS AVONS ETUDIE LE CONCEPT DE FILTRE IMPLICITE DEVELOPPE PAR MASON ET SES COLLEGUES, A TRAVERS DES MODELES AYANT UNE LONGUEUR DE COUPURE SUPERIEURE AU PAS D'ESPACE. EN S'APPUYANT SUR L'ANALYSE THEORIQUE DU FILTRAGE SPATIAL, SUR L'ETUDE DES FILTRES PROPOSEE PAR MUSCHINSKY, ET SUR LES CALCULS DE TURBULENCE HOMOGENE ISOTROPE (THI), NOUS AVONS DETERMINE LE FILTRE ASSOCIE AUX MODELES DE SMAGORINSKY ET DE SCHUMANN. NOUS AVONS OBSERVE UN COMPORTEMENT ASYMPTOTIQUE ET L'INDEPENDANCE DES FILTRES AUX SCHEMAS NUMERIQUES LORSQUE LA LONGUEUR DE COUPURE AUGMENTE A MAILLAGE FIXE. DANS UN SECOND TEMPS, DEUX NOUVEAUX MODELES SOUS-MAILLES A DEUX EQUATIONS ONT ETE DEVELOPPES. LE PREMIER, ISSU DU MODELE DE SCHUMANN, EST A ECHELLES MULTIPLES. LE SECOND EST BASE SUR LES EQUATIONS DE L'ENERGIE CINETIQUE SOUS-MAILLE ET DU TAUX DE DISSIPATION. CES MODELES ONT ETE VALIDES PAR DES CALCULS DE THI ET DE COUCHE DE MELANGE TEMPORELLE 3D. ENFIN, SUR DES CALCULS DE COUCHE DE MELANGE, IL APPARAIT QUE LES CALCULS 2D SONT INCAPABLES DE RENDRE COMPTE CORRECTEMENT DES PHENOMENES PHYSIQUES (TOPOLOGIE ET STRUCTURES DE L'ECOULEMENT, EVOLUTION DES GRANDEURS MOYENNES, PROFILS STATISTIQUES). LES RESULTATS OBTENUS PERMETTENT D'ENVISAGER DE FUTURS DEVELOPPEMENTS : ETUDES DES FILTRES SUR DES MAILLAGES IRREGULIERS, EXTENSIONS DES NOUVEAUX MODELES AUX CAS ANISOTROPES ET AUX ECOULEMENTS AVEC PAROI.
Download or read book Subsonic Aerodynamics written by Ion Paraschivoiu and published by Presses inter Polytechnique. This book was released on 2003 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.
Download or read book Rheophysics written by Philippe Coussot and published by Springer. This book was released on 2014-06-17 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a unified view of the physicochemical origin of the mechanical behaviour of gases, simple solids and liquids, suspensions, polymers, emulsions, foams, and granular materials, along with techniques for measuring that behaviour. Besides molecular materials in all their classical gaseous, solid, or liquid states, we deal daily with a number of other materials made of coarser elements such as polymers, cells, grains, bubbles, and droplets. They take on the familiar appearance of paints, inks, cements, muds, foams, emulsions, toothpastes, gels, etc. These materials exhibit complex structures and sometimes amazing types of mechanical behaviour, often intermediate between those of a simple liquid and a simple solid. From a practical standpoint, the aim is to analyze their internal evolution (aging, restructuring, phase separation, etc.), then to formulate these materials in accordance with the desired properties, and thereby devise new materials. With that aim in mind, it is crucial to understand how these materials deform or flow, depending on the interactions and structures formed by the elements they contain. This book is intended for students as well as more advanced researchers in mechanics, physics, chemistry, and biology. The mathematical formalism is reduced in order to focus on physical explanations.
Download or read book The Theory of Ionization of Gases by Collision written by Sir John Townsend and published by . This book was released on 1910 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Number System written by H. A. Thurston and published by Courier Corporation. This book was released on 2012-10-23 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book explores arithmetic's underlying concepts and their logical development, in addition to a detailed, systematic construction of the number systems of rational, real, and complex numbers. 1956 edition.
Download or read book Properties of UO2 written by J. Belle and published by . This book was released on 1957 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanics of Porous Media written by Philippe Charlez and published by CRC Press. This book was released on 1995-01-01 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents the lecture notes of the 1994 Mechanics of Porous Media Summer School. Chapters cover theoretical basics, methods for measuring poroelastic coefficients, numerical implementation and applications.
Download or read book Solid Propellant Rocket Research written by Martin Summerfield and published by Elsevier. This book was released on 2013-11-11 with total page 713 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid Propellant Rocket Research
Download or read book Subsurface water Flow and Solute Transport written by and published by . This book was released on 1989 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Structure of Atmospheric Turbulence written by John Leask Lumley and published by . This book was released on 1964 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In Vessel Melt Retention and Ex Vessel Corium Cooling IAEA Tecdoc No 1906 written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2020-08-06 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication results from a technical meeting on phenomenology and technologies relevant to in-vessel melt retention (IVMR) and ex-vessel corium cooling (EVCC). The purpose of the publication is to capture the state of knowledge, at the time of that meeting, related to phenomenology and technologies as well as the challenges and pending issues relevant to IVMR and EVCC for water cooled reactors by summarizing the information provided by the meeting participants in a form useful to practitioners in Member States.
Download or read book Mathematical Modeling in Optical Science written by Gang Bao and published by SIAM. This book was released on 2001-01-01 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume addresses recent developments in mathematical modeling in three areas of optical science: diffractive optics, photonic band gap structures, and waveguides. Particular emphasis is on the formulation of mathematical models and the design and analysis of new computational approaches. The book contains cutting-edge discourses on emerging technology in optics that provides significant challenges and opportunities for applied mathematicians, researchers, and engineers. Each of the three topics is presented through a series of survey papers to provide a broad overview focusing on the mathematical models. Chapters present model problems, physical principles, mathematical and computational approaches, and engineering applications corresponding to each of the three areas. Although some of the subject matter is classical, the topics presented are new and represent the latest developments in their respective fields.
Download or read book The Paran River Basin written by Chris D. Metcalfe and published by Routledge. This book was released on 2020-06-10 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides insight into the hydrology, ecosystem services and management of water resources in the Paraná River basin, including the importance of water to the socio-economic development of the countries within the watershed. Running through Brazil. Paraguay and Argentina, the Paraná River and its watershed is home to some of South America's major population centers as well as important ecosystems threatened by development. At the same time, the river is a major resource driving the economies of the nations within its boundaries. This volume examines the impacts of environmental degradation, and the tradeoffs between the energy sector and the maintenance of ecosystem services. In particular, it focuses on the threats from development to sensitive ecosystems within the basin and the challenges of transboundary management of water resources. In addition to presenting wider perspectives on water management, the volume specifically covers water infrastructure, aquatic ecosystems, water quality, geomorphological influences and the impact of climate change. Finally, by assessing each country's current status in meeting the Sustainable Development Goals this volume provides a timely analysis as national governments within the basin are becoming increasingly concerned about the sustainability of the freshwater ecosystems within the Paraná River basin. This book will be of great interest to students and scholars of water and natural resource management, environmental policy, sustainable development and Latin American studies. It will also be relevant to water management professionals.
