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Author: Christian Vanhille
Publisher:
ISBN:
Category :
Languages : fr
Pages : 337
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Book Description
DANS LE DOMAINE DE L'ACOUSTIQUE SOUS-MARINE, LA METHODE DES EQUATIONS INTEGRALES EST COURAMMENT UTILISEE POUR MODELISER LE RAYONNEMENT OU LA DIFFRACTION D'UNE ONDE ACOUSTIQUE PAR UNE STRUCTURE IMMERGEE. LES CHAMPS DE PRESSION DANS LE FLUIDE ENVIRONNANT SONT EVALUES A PARTIR DU SIMPLE MAILLAGE DE LA SURFACE DU CORPS. LA SOLUTION N'EST PAS UNIQUE POUR CERTAINES FREQUENCES DITES IRREGULIERES. LE CODE EQI UTILISE LA REPRESENTATION INTEGRALE DE HELMHOLTZ EXTERIEURE ET TRAITE LE PROBLEME D'UNICITE PAR EMPLOI DE LA METHODE DE JONES: LE SYSTEME EQUATIONS INTEGRALES EST SURDETERMINE PAR DES EQUATIONS DE CHAMP NUL. LORS D'UNE ANALYSE ACOUSTIQUE SUR UNE LARGE GAMME DE FREQUENCES, LA CONSTRUCTION DES MATRICES EQUATIONS INTEGRALES EST TRES COUTEUSE EN TEMPS DE CALCUL. UN NOUVEL ALGORITHME EQUATIONS INTEGRALES AUTOMATIQUE BASE SUR UNE INTERPOLATION FREQUENTIELLE EST PROPOSE. IL PERMET UN GAIN DE TEMPS DE CALCUL IMPORTANT QUI AUGMENTE AVEC LA TAILLE DU PROBLEME SANS PERTE DE PRECISION. L'EMPLOI DE FONCTIONS D'ONDES SPHERIQUES DANS LES EQUATIONS DE CHAMP NUL GENERE DES DIFFICULTES DE SIMULATION DES STRUCTURES EXCENTREES. UNE NOUVELLE INTERPOLATION DE LA PRESSION SIMPLIFIE L'UTILISATION DU MODELE. DE PLUS, UNE TECHNIQUE ADAPTEE AUX GEOMETRIES EXCENTREES EST DEVELOPPEE. L'UTILISATION DU CHAMP NUL EST AINSI GRANDEMENT SIMPLIFIEE ET LA DEPENSE EN TEMPS DE CALCUL DIMINUEE. LE CALCUL AUX FREQUENCES IRREGULIERES DE STRUCTURES COMPOSEES DE PLUSIEURS VOLUMES EST DESORMAIS POSSIBLE. DE NOMBREUX EXEMPLES ILLUSTRENT LES TRAVAUX PRESENTES. UNE APPLICATION AU COUPLAGE FLUIDE-STRUCTURE EST EFFECTUEE PAR COMBINAISON ENTRE LE CODE EQI ET LE CODE ELEMENTS FINIS ATILA. CETTE THESE ABOUTIT A UNE NOUVELLE VERSION DU CODE EQI CAPABLE DE MODELISER DES STRUCTURES DE PLUS EN PLUS COMPLEXES, POUR DES FREQUENCES DE PLUS EN PLUS ELEVEES
Author: Christian Vanhille
Publisher:
ISBN:
Category :
Languages : fr
Pages : 337
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Book Description
DANS LE DOMAINE DE L'ACOUSTIQUE SOUS-MARINE, LA METHODE DES EQUATIONS INTEGRALES EST COURAMMENT UTILISEE POUR MODELISER LE RAYONNEMENT OU LA DIFFRACTION D'UNE ONDE ACOUSTIQUE PAR UNE STRUCTURE IMMERGEE. LES CHAMPS DE PRESSION DANS LE FLUIDE ENVIRONNANT SONT EVALUES A PARTIR DU SIMPLE MAILLAGE DE LA SURFACE DU CORPS. LA SOLUTION N'EST PAS UNIQUE POUR CERTAINES FREQUENCES DITES IRREGULIERES. LE CODE EQI UTILISE LA REPRESENTATION INTEGRALE DE HELMHOLTZ EXTERIEURE ET TRAITE LE PROBLEME D'UNICITE PAR EMPLOI DE LA METHODE DE JONES: LE SYSTEME EQUATIONS INTEGRALES EST SURDETERMINE PAR DES EQUATIONS DE CHAMP NUL. LORS D'UNE ANALYSE ACOUSTIQUE SUR UNE LARGE GAMME DE FREQUENCES, LA CONSTRUCTION DES MATRICES EQUATIONS INTEGRALES EST TRES COUTEUSE EN TEMPS DE CALCUL. UN NOUVEL ALGORITHME EQUATIONS INTEGRALES AUTOMATIQUE BASE SUR UNE INTERPOLATION FREQUENTIELLE EST PROPOSE. IL PERMET UN GAIN DE TEMPS DE CALCUL IMPORTANT QUI AUGMENTE AVEC LA TAILLE DU PROBLEME SANS PERTE DE PRECISION. L'EMPLOI DE FONCTIONS D'ONDES SPHERIQUES DANS LES EQUATIONS DE CHAMP NUL GENERE DES DIFFICULTES DE SIMULATION DES STRUCTURES EXCENTREES. UNE NOUVELLE INTERPOLATION DE LA PRESSION SIMPLIFIE L'UTILISATION DU MODELE. DE PLUS, UNE TECHNIQUE ADAPTEE AUX GEOMETRIES EXCENTREES EST DEVELOPPEE. L'UTILISATION DU CHAMP NUL EST AINSI GRANDEMENT SIMPLIFIEE ET LA DEPENSE EN TEMPS DE CALCUL DIMINUEE. LE CALCUL AUX FREQUENCES IRREGULIERES DE STRUCTURES COMPOSEES DE PLUSIEURS VOLUMES EST DESORMAIS POSSIBLE. DE NOMBREUX EXEMPLES ILLUSTRENT LES TRAVAUX PRESENTES. UNE APPLICATION AU COUPLAGE FLUIDE-STRUCTURE EST EFFECTUEE PAR COMBINAISON ENTRE LE CODE EQI ET LE CODE ELEMENTS FINIS ATILA. CETTE THESE ABOUTIT A UNE NOUVELLE VERSION DU CODE EQI CAPABLE DE MODELISER DES STRUCTURES DE PLUS EN PLUS COMPLEXES, POUR DES FREQUENCES DE PLUS EN PLUS ELEVEES
Author: El Houcine Jaddi
Publisher:
ISBN:
Category :
Languages : fr
Pages : 190
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Book Description
Nous nous sommes attachés dans ce travail à résoudre le problème de diffraction d'une onde acoustique cylindrique ou sphérique, par un corps rigide, de forme arbitraire. Ceci nous a conduit à une formulation en équations intégrales résolues numériquement. Nous avons d'abord formulé le problème de diffraction acoustique et ensuite présenté la méthode directe, basée sur l'équation intégrale de surface de Helmholtz ou sa dérivée normale, et la méthode des potentiels de couche. Le schéma d'approximation utilisé en tridimensionnel est celui où la surface mince est approchée par une juxtaposition de rectangles (plans ou courbes) et le saut du potentiel de surface est pris constant pas élément. En bidimensionnel, la frontière de l'obstacle est approchée par des segments de droites et l'approximation du potentiel de surface est une combinaison linéaire de simples fonctions polynomiales de degré 1, basées sur les points de contour qui sont pris équidistants les uns des autres pour simplifier. Enfin, nous avons appliqué ce code numérique à la détermination de la diffraction (ou diagrammes de directivité) par des écrans usuels de protection acoustique, placés en bordure d'une autoroute, d'un aéroport ou pour réduire le bruit du "jets", tel qu'un mur en présence d'un sol parfaitement réfléchissant (en 2D), une plaque mince rigide ou un demi-cylindre (en 3 D). Nous trouvons que les méthodes de calcul utilisées convergent pour un choix d'élements de dimensions inférieures ou égales à /6, ou est la longueur d'onde du son émis. La confrontation des résultats calculés avec ceux provenant de mesures expérimentales montre qu'ils concordent d'une manière satisfaisante. Dans ces approches, la source sonore étant soit cylindrique (pour un écran fini 2D), soit sphérique (pour un écran fini 3D), soit modélisée par une distribution de sources ponctuelles incohérentes et statistiquement indépendantes réparties sur l'axe de l'écran demi-cylindriques.
Author: Jean-Marie Berthelot
Publisher: Springer
ISBN: 9781461268031
Category : Technology & Engineering
Languages : en
Pages : 0
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Book Description
Mechanical engineering, an engineering discipline borne of the needs of the in dustrial revolution, is once again asked to do its substantial share in the call for industrial renewal. The general call is urgent as we face profound issues of produc tivity and competitiveness that require engineering solutions, among others. The Mechanical Engineering Series features graduate texts and research monographs intended to address the need for information in contemporary areas of mechanical engineering. The series is conceived as a comprehensive one that covers a broad range of concentrations important to mechanical engineering graduate education and re search. We are fortunate to have a distinguished roster of consulting editors on the advisory board, each an expert in one of the areas of concentration. The names of the consulting editors are listed on the next page of this volume. The areas of concentration are applied mechanics, biomechanics, computational mechan ics, dynamic systems and control, energetics, mechanics of materials, processing, thermal science, and tribology.
Author: Fabio Remondino
Publisher: Springer Science & Business Media
ISBN: 3642275230
Category : Technology & Engineering
Languages : en
Pages : 243
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Book Description
Today the cost of solid-state two-dimensional imagers has dramatically dropped, introducing low cost systems on the market suitable for a variety of applications, including both industrial and consumer products. However, these systems can capture only a two-dimensional projection (2D), or intensity map, of the scene under observation, losing a variable of paramount importance, i.e., the arrival time of the impinging photons. Time-Of-Flight (TOF) Range-Imaging (TOF) is an emerging sensor technology able to deliver, at the same time, depth and intensity maps of the scene under observation. Featuring different sensor resolutions, RIM cameras serve a wide community with a lot of applications like monitoring, architecture, life sciences, robotics, etc. This book will bring together experts from the sensor and metrology side in order to collect the state-of-art researchers in these fields working with RIM cameras. All the aspects in the acquisition and processing chain will be addressed, from recent updates concerning the photo-detectors, to the analysis of the calibration techniques, giving also a perspective onto new applications domains.
Author: Philippe Gourbesville
Publisher: Springer
ISBN: 9812876154
Category : Science
Languages : en
Pages : 616
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Book Description
This book is a collection of extended papers based on presentations given during the SIMHYDRO 2014 conference, held in Sophia Antipolis in June 2014. It focuses on the modeling and simulation of fast hydraulic transients, on 3D modeling, and on uncertainties and multiphase flows. The book explores both the limitations and performance of current models and presents the latest developments based on new numerical schemes, high-performance computing, multiphysics and multiscale methods, and better interaction with field or scale model data. It addresses the interests of practitioners, stakeholders, researchers and engineers active in this field.
Author: Jean Daillant
Publisher: Springer Science & Business Media
ISBN: 3540486968
Category : Science
Languages : en
Pages : 347
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Book Description
The reflection of and neutrons from surfaces has existed as an x-rays exp- imental for almost it is in the last technique fifty Nevertheless, only years. decade that these methods have become as of enormously popular probes This the surfaces and interfaces. to be due to of several appears convergence of intense different circumstances. These include the more n- availability be measured orders tron and sources that can over (so reflectivity x-ray many of and the much weaker surface diffuse can now also be magnitude scattering of thin films and studied in some the detail); growing importance multil- basic the realization of the ers in both and technology research; important which in the of surfaces and and role roughness plays properties interfaces; the of statistical models to characterize the of finally development topology its and its characterization from on roughness, dependence growth processes The of and to surface scattering experiments. ability x-rays neutro4s study four five orders of in scale of surfaces over to magnitude length regardless their and also their to ability probe environment, temperature, pressure, etc. , makes these the choice for buried interfaces often probes preferred obtaining information about the microstructure of often in statistical a global surfaces, the local This is manner to complementary imaging microscopy techniques, of such studies in the literature witnessed the veritable by explosion published the last few Thus these lectures will useful for over a resource years.
Author: Gian-Franco Dalla Betta
Publisher: BoD – Books on Demand
ISBN: 953307163X
Category : Technology & Engineering
Languages : en
Pages : 482
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Book Description
Photodiodes, the simplest but most versatile optoelectronic devices, are currently used in a variety of applications, including vision systems, optical interconnects, optical storage systems, photometry, particle physics, medical imaging, etc. Advances in Photodiodes addresses the state-of-the-art, latest developments and new trends in the field, covering theoretical aspects, design and simulation issues, processing techniques, experimental results, and applications. Written by internationally renowned experts, with contributions from universities, research institutes and industries, the book is a valuable reference tool for students, scientists, engineers, and researchers.
Author:
Publisher: Academic Press
ISBN: 0123876966
Category : Science
Languages : en
Pages : 593
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Book Description
Single-photon generation and detection is at the forefront of modern optical physics research. This book is intended to provide a comprehensive overview of the current status of single-photon techniques and research methods in the spectral region from the visible to the infrared. The use of single photons, produced on demand with well-defined quantum properties, offers an unprecedented set of capabilities that are central to the new area of quantum information and are of revolutionary importance in areas that range from the traditional, such as high sensitivity detection for astronomy, remote sensing, and medical diagnostics, to the exotic, such as secretive surveillance and very long communication links for data transmission on interplanetary missions. The goal of this volume is to provide researchers with a comprehensive overview of the technology and techniques that are available to enable them to better design an experimental plan for its intended purpose. The book will be broken into chapters focused specifically on the development and capabilities of the available detectors and sources to allow a comparative understanding to be developed by the reader along with and idea of how the field is progressing and what can be expected in the near future. Along with this technology, we will include chapters devoted to the applications of this technology, which is in fact much of the driver for its development. This is set to become the go-to reference for this field. - Covers all the basic aspects needed to perform single-photon experiments and serves as the first reference to any newcomer who would like to produce an experimental design that incorporates the latest techniques - Provides a comprehensive overview of the current status of single-photon techniques and research methods in the spectral region from the visible to the infrared, thus giving broad background that should enable newcomers to the field to make rapid progress in gaining proficiency - Written by leading experts in the field, among which, the leading Editor is recognized as having laid down the roadmap, thus providing the reader with an authenticated and reliable source
Author: Franz Rothe
Publisher: Springer
ISBN: 3540389172
Category : Science
Languages : en
Pages : 222
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Book Description
Author: International Atomic Energy Agency
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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