Download or read book Dynamique non lin aire et cascade en turbulences written by Annette Cazaubiel and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les modèles de turbulence tendent à prédire l'évolution statistique d'un champ régi par une équation non-linéaire avec des termes de forçage et de dissipation. Pour la turbulence hydrodynamique, le champ de vitesse est gouverné par l'équation de Navier-Stokes. Pour décrire un champ d'ondes aléatoires faiblement non-linéaires en interaction, la théorie de la turbulence d'ondes permet d'obtenir des prédictions sur de nombreuses quantités statistiques. Lorsqu'un champ d'ondes stochastiques obéit à une équation intégrable, on parle de turbulence intégrable. Ces différentes « turbulences » restent des défis théoriques. Afin de mieux les comprendre, il est nécessaire de confronter ces théories à des expériences de laboratoire. Nous avons mené dans cette thèse des études expérimentales sur trois systèmes non-linéaires turbulents. Nous avons mis en place au laboratoire un nouveau dispositif pour engendrer la turbulence hydrodynamique tridimensionnelle. En utilisant des particules magnétiques de petites tailles contrôlées à distance, nous arrivons à forcer le fluide en volume, aléatoirement en espace et en temps. Nous présentons dans cette thèse les principales caractéristiques de la turbulence à petites échelles ainsi engendrée et des résultats sur la dynamique des grandes échelles (échelles plus grand que celle du forçage) en turbulence homogène, isotrope. En utilisant la centrifugeuse de l'ESA, nous avons pu mener des expériences de turbulence d'ondes à la surface d'un fluide en faisant varier la gravité effective jusqu'à 20 fois la gravité terrestre. Nous avons pu notamment montrer l'importance des effets de taille finie du système dans les expériences de turbulence d'ondes. Enfin, en utilisant le grand bassin de l'École Centrale de Nantes, nous avons étudié la propagation unidimensionnelle d'ondes de gravité aléatoires en eau profonde, et la statistique de l'émergence de structures localisées non-linéaires telles que des solitons évoluant sur un fond d'ondes stochastiques. Nous avons mené dans cette thèse trois études expérimentales de systèmes non-linéaires, turbulents. Nous avons mis en place un nouveau dispositif pour engendrer la turbulence hydrodynamique 3-D. En utilisant des particules magnétiques de petites tailles contrôlées à distance, nous arrivons à forcer le fluide en volume, aléatoirement en espace et en temps. Nous présentons dans cette thèse les principales caractéristiques de la turbulence ainsi engendrée et notamment comment le forçage en volume permet d'obtenir une cascade turbulente à des nombres de Reynolds modérés. Grâce à la centrifugeuse de l'ESA, nous avons pu mener des expériences de turbulence d'ondes en faisant varier la gravité effective jusqu'à 20 fois la gravité terrestre. Nous avons pu montrer l'importance des modes grandes échelles du bassin dans les expériences de turbulence d'ondes. Dans le grand bassin et le canal à traction de l'École Centrale de Nantes, nous avons étudié la propagation unidimensionnelle d'ondes de gravité, en eau profonde, modulées aléatoirement en amplitude et en phase, et l'émergence de structures localisées non linéaires et de solitons évoluant sur un fond d'ondes stochastiques. Une telle coexistence est prédite théoriquement pour la turbulence intégrable.
Download or read book Dynamique Non lin aire Et Le Chaos written by and published by . This book was released on 1993 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Intermittence en turbulence pleinement d velopp e et en dynamique non lin aire written by Aurore Naso and published by . This book was released on 2005 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette thèse se compose de deux parties. Dans la première est étudié un modèle de turbulence hydrodynamique se présentant sous la forme d’un système d’équations différentielles stochastiques. On présente dans un premier temps les solutions de ce système calculées dans l’approximation semi-classique, puis celles obtenues par une méthode de type Monte-Carlo adaptée au problème, dans le cas où le forçage est supposé statistiquement homogène et isotrope. Ces solutions présentent un bon accord avec des résultats d’expériences et de simulations numériques directes de l’équation de Navier-Stokes. Dans un second temps sont présentées les solutions du système lorsqu’un cisaillement est appliqué à l’écoulement. La seconde partie est consacrée à l’étude de la transition au chaos spatio-temporel par intermittence dans un système hydrodynamique. Cette transition est d’abord étudiée quantitativement, puis un modèle d’intermittence spatio-temporelle est appliqué aux conditions aux limites de l’expérience. Comme le système réel, les solutions de ce modèle présentent pour certaines valeurs des paramètres dont dépend un régime de bistabilité, près du seuil, entre l’intermittence spatio-temporelle et un régime où le désordre n’est présent que sur les bords.
Download or read book AGARD Lecture Series written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development and published by . This book was released on 1993 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Eddy Simulations of Turbulence written by M. Lesieur and published by Cambridge University Press. This book was released on 2005-08-22 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-Eddy Simulations of Turbulence is a reference for LES, direct numerical simulation and Reynolds-averaged Navier-Stokes simulation.
Download or read book Literature 1984 Part 2 written by S. Böhme and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 928 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Logos et th orie des catastrophes written by Jean Petitot and published by Patino. This book was released on 1988 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vocabulaire des syst mes dynamiques et de l imagerie fractale written by Silvia Pavel and published by . This book was released on 1994 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 30 Years of the Landau Institute written by Isaak Markovich Khalatnikov and published by World Scientific. This book was released on 1996 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Landau Institute for Theoretical Physics was created in 1965 by a group of LD Landau's pupils. Very soon, it was widely recognized as one of the world's leading centers in theoretical physics. According to Science Magazine, the Institute in the eighties had the highest citation index among all the scientific organizations in the former Soviet Union. This collection of the best papers of the Institute reflects the development of the many directions in the exact sciences during the last 30 years. The reader can find the original formulations of well-known notions in condensed matter theory, quantum field theory, mathematical physics and astrophysics, which were introduced by members of the Landau Institute.The following are some of the achievements described in this book: monopoles (A Polyakov), instantons (A Belavin et al.), weak crystallization (S Brazovskii), spin superfluidity (I Fomin), finite band potentials (S Novikov) and paraconductivity (A Larkin, L Aslamasov).
Download or read book Comptes rendus de l Acad mie des sciences written by and published by . This book was released on 1997-07 with total page 908 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Water Waves The Mathematical Theory with Applications written by James Johnston Stoker and published by Courier Dover Publications. This book was released on 2019-04-17 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: First published in 1957, this is a classic monograph in the area of applied mathematics. It offers a connected account of the mathematical theory of wave motion in a liquid with a free surface and subjected to gravitational and other forces, together with applications to a wide variety of concrete physical problems. A never-surpassed text, it remains of permanent value to a wide range of scientists and engineers concerned with problems in fluid mechanics. The four-part treatment begins with a presentation of the derivation of the basic hydrodynamic theory for non-viscous incompressible fluids and a description of the two principal approximate theories that form the basis for the rest of the book. The second section centers on the approximate theory that results from small-amplitude wave motions. A consideration of problems involving waves in shallow water follows, and the text concludes with a selection of problems solved in terms of the exact theory. Despite the diversity of its topics, this text offers a unified, readable, and largely self-contained treatment.
Download or read book Les Ondelettes en 1989 written by Pierre G. Lemarie and published by Springer. This book was released on 2006-11-14 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book surveys the recent theory of wavelet transforms and its applications in various fields both within mathematics (singular integrals, localization of singularities) and beyond it, in computer vision, the physics of fractals, time-frequency analysis.
Download or read book Acoustics Aeroacoustics and Vibrations written by Fabien Anselmet and published by John Wiley & Sons. This book was released on 2016-01-07 with total page 529 pages. Available in PDF, EPUB and Kindle. Book excerpt: This didactic book presents the main elements of acoustics, aeroacoustics and vibrations. Illustrated with numerous concrete examples linked to solid and fluid continua, Acoustics, Aeroacoustics and Vibrations proposes a selection of applications encountered in the three fields, whether in room acoustics, transport, energy production systems or environmental problems. Theoretical approaches enable us to analyze the different processes in play. Typical results, mostly from numerical simulations, are used to illustrate the main phenomena (fluid acoustics, radiation, diffraction, vibroacoustics, etc.).
Download or read book Physics of Solitons written by Thierry Dauxois and published by Cambridge University Press. This book was released on 2006-03-09 with total page 435 pages. Available in PDF, EPUB and Kindle. Book excerpt: This textbook gives an instructive view of solitons and their applications for advanced students of physics.
Download or read book Instabilities and Nonequilibrium Structures written by E. Tirapegui and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Approach your problems from the right end It isn't that they can't see the solution. It is and begin with the answers. Then one day, that they can't see the problem. perbaps you will find the final question. G. K. Chesterton. The Scandal of Father 'The Hermit Clad in Crane Feathers' in R. Brown 'The point of a Pin'. van GuIik's The Chinese Maze Murders. Growing specialization and diversification have brought a host of monographs and textbooks on increasingly specialized topics. However, the "tree" of knowledge of mathematics and related fields does not grow only by putting forth new branches. It also happens, quite often in fact, that branches which were thought to be completely disparate are suddenly seen to be related. Further, the kind and level of sophistication of mathematics applied in various sciences has changed drastically in recent years: measure theory is used (non-trivially) in regional and theoretical economics; algebraic geometry interacts with physics; the Minkowsky lemma, coding theory and the structure of water meet one another in packing and covering theory; quantum fields, crystal defects and mathematical programming profit from homotopy theory; Lie algebras are relevant to filtering; and prediction and electrical engineering can use Stein spaces. And in addition to this there are such new emerging subdisciplines as "experimental mathematics", "CFD", "completely integrable systems", "chaos, synergetics and large-scale order", which are almost impossible to fit into the existing classification schemes. They draw upon widely different sections of mathematics.
Download or read book Mesoscale Meteorological Modeling written by Roger A. Pielke and published by Academic Press. This book was released on 2002 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt: This second edition provides an update of the field of mesoscale atmospheric modeling. The topic of mesoscale modeling is developed from basic concepts in atmospheric physics. New numerical and analytical tools are introduced. Problem sets are provided to test the comprehension of the material introduced in the text.
