Download or read book Stabilit lin aire et faiblement non lin aire d une couche limite laminaire incompressible par un syst me d quations parabolis PSE written by Christophe Airiau and published by . This book was released on 1994 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les équations de stabilité sont parabolisées dans la direction x longitudinale de l'écoulement (équations PSE). A la théorie classique, locale, linéaire parallèle d'Orr-Sommerfeld, est substitué un problème d'évolution résolu par une simple marche en x. Cette nouvelle approche permet de traiter simplement et simultanément les effets non parallèles et les effets faiblement non linéaires. En théorie linéaire, après des comparaisons avec la théorie parallèle, la méthode des échelles multiples, des résultats expérimentaux et avec des Simulations Numériques Directes (DNS), on trouve des effets non parallèles importants pour des perturbations et des écoulements moyens tridimensionnels. En théorie faiblement non linéaire, les résonances fondamentale et subharmonique sont obtenues pour des couches limites bidimensionnelles. On montre que les PSE sont en accord avec les expériences, la théorie de l'instabilité secondaire, et les DNS, pour les écoulements de similitude de Falkner-Skan. L'état de saturation en amplitude des perturbations instationnaires ainsi que l'augmentation du coefficient de frottement près du début de la transition sont ainsi mis en évidence. Enfin, l'approche PSE est appliquée sur des expériences faites au CERT-ONERA, pour des écoulements de couche limite quelconques avec de forts gradients de pression.
Download or read book Stabilit lin aire et faiblement non lin aire d une couche limite pour un fluide incompressible avec l approche PSE written by Marie-Laurence Copie and published by . This book was released on 1996 with total page 259 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cette thèse est consacrée à l'étude de la stabilité d'une couche limite en fluide incompressible. On a considéré des écoulements bidimensionnels et le cas d'une couche limite se développant sur une aile en flèche. Nous avons utilisé le modèle PSE (Parabolized Stability Equations) proposé par Herbert. Ce modèle permet de s'affranchir de l'hypothèse d'écoulement parallèle nécessaire pour la théorie locale (Orr-Sommerfeld). Il permet en outre de prendre en compte des interactions non linéaires. Les codes développés, en bidimensionnel et en tridimensionnel, ont permis d'apporter des éclairages nouveaux sur les mécanismes d'instabilité : mécanismes de résonance en 2D (résonances subharmonique et fondamentale), effets non parallèles en 3D (effet déstabilisant de saturation des amplitudes), mécanismes non linéaires en 3D (phénomène de saturation des amplitudes). On a notamment analysé des résultats expérimentaux obtenus au Département. Ces résultats représentent une contribution au problème de la prévision de la transition naturelle ; toutefois, l'étude des mécanismes non linéaires en tridimensionnel doit être poursuivie. Cette étude doit également être complétée par des études de réceptivité.
Download or read book Stabilit lin aire et faiblement non lin aire d une couche limite laminaire compressible tridimensionnelle par l approche PSE written by Hervé Salinas and published by . This book was released on 1998 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stabilisation et contr le optimal des quations de Prandtl written by Jean-Marie Buchot and published by . This book was released on 2002 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nous étudions la stabilisation d’un écoulement 2D, incompressible, sur une plaque plane par un contrôle feedback correspondant à une vitesse d’aspiration pariétale située près du bord d’attaque. Dans la couche limite laminaire, l’écoulement est modélisé par les équations de Prandtl. Une perturbation d’un écoulement stationnaire étant donnée, nous recherchons une loi de contrôle permettant de stabiliser les variations de la position de transition du régime laminaire au régime turbulent. Cette loi est calculée par résolution d’un problème LQR posé en horizon infini. A l’aide de la transformation dite de Crocco, le système de Prandtl se réduit à une équation parabolique fortement dégénérée linéarisée (l’équation d’état du problème LQR). Dans ce contexte, l’étude de l’équation de Riccati algébrique du problème de contrôle n’est pas standard. Nous avons développé un schéma Différences finies / Volumes finis pour résoudre les modèles non linéaire et linéarisé. Différents tests numériques permettent de mesurer l’efficacité de la loi de feedback appliquée au modèle non linéaire, dans le cas d’observations partielles et bruitées du système.
Download or read book Basics of Aerothermodynamics written by Ernst Heinrich Hirschel and published by Springer Science & Business Media. This book was released on 2006-01-16 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: The last two decades have brought two important developments for aeroth- modynamics. One is that airbreathing hypersonic flight became the topic of technology programmes and extended system studies. The other is the emergence and maturing of the discrete numerical methods of aerodyn- ics/aerothermodynamics complementary to the ground-simulation facilities, with the parallel enormous growth of computer power. Airbreathing hypersonic flight vehicles are, in contrast to aeroassisted re-entry vehicles, drag sensitive. They have, further, highly integrated lift and propulsion systems. This means that viscous eflFects, like boundary-layer development, laminar-turbulent transition, to a certain degree also strong interaction phenomena, are much more important for such vehicles than for re-entry vehicles. This holds also for the thermal state of the surface and thermal surface effects, concerning viscous and thermo-chemical phenomena (more important for re-entry vehicles) at and near the wall. The discrete numerical methods of aerodynamics/aerothermodynamics permit now - what was twenty years ago not imaginable - the simulation of high speed flows past real flight vehicle configurations with thermo-chemical and viscous effects, the description of the latter being still handicapped by in sufficient flow-physics models. The benefits of numerical simulation for flight vehicle design are enormous: much improved aerodynamic shape definition and optimization, provision of accurate and reliable aerodynamic data, and highly accurate determination of thermal and mechanical loads. Truly mul- disciplinary design and optimization methods regarding the layout of thermal protection systems, all kinds of aero-servoelasticity problems of the airframe, et cetera, begin now to emerge.
Download or read book Etude d une quation parabolique non lin aire d g n r e li e la th orie de la couche limite written by Michel Misiti and published by . This book was released on 1978 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: ON CHERCHE LES SOLUTIONS FAIBLES D'UNE EQUATION REGISSANT L'ECOULEMENT D'UN FLUIDE AU VOISINAGE D'UNE PLAQUE; CET ECOULEMENT EST BI-DIMENSIONNEL, STATIONNAIRE ET INCOMPRESSIBLE. ON ETUDIE LE CAS OU LE GRADIENT DE PRESSION EST NEGATIF OU NUL. ON RESOUT LE SYSTEME D ROND U/D ROND T-NU D ROND /D ROND X(UD ROND U/D ROND X)+V::(0) D ROND U/D ROND X/D ROND X+G/U=0 DANS (0,T(X)0,M( U(T,0)=0, U(T,M)=U::(0)0(T), U(0,X)=U::(0)(X). POUR LES CAS DU::(INFINI)/DT=0=>G=-0; DU::(INFINI)/DT >OU= 0=>G
Download or read book Hypersonic Flow Theory written by Wallace Hayes and published by Elsevier. This book was released on 2012-12-02 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hypersonic Flow Theory presents the fundamentals of fluid mechanics, focusing on the hypersonic flow theory and approaches in theoretical aerodynamics. This book discusses the assumptions underlying hypersonic flow theory, unified supersonic-hypersonic similitude, two-dimensional and axisymmetric bodies, and circular cylinder. The constant-streamtube-area approximation, streamtube-continuity methods, and tangent-wedge and tangent-cone are also deliberated. This text likewise covers the similar laminar boundary layer solutions, bluntness induced interactions on slender bodies, and free molecule transfer theory. The dynamics of hypersonic flight or hypersonic wing theory, magnetohydrodynamic theory, or any developments involving treatment of the Boltzmann equation are not included. This publication is intended for hypersonic aerodynamicists, students, and researchers conducting work on the hypersonic flow phenomena.
Download or read book Hypersonic Aerothermodynamics written by John J. Bertin and published by AIAA. This book was released on 1994 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt: A modern treatment of hypersonic aerothermodynamics for students, engineers, scientists, and program managers involved in the study and application of hypersonic flight. It assumes an understanding of the basic principles of fluid mechanics, thermodynamics, compressible flow, and heat transfer. Ten chapters address: general characterization of hypersonic flows; basic equations of motion; defining the aerothermodynamic environment; experimental measurements of hypersonic flows; stagnation-region flowfield; the pressure distribution; the boundary layer and convective heat transfer; aerodynamic forces and moments; viscous interactions; and aerothermodynamics and design considerations. Includes sample exercises and homework problems. Annotation copyright by Book News, Inc., Portland, OR
Download or read book New Results in Numerical and Experimental Fluid Mechanics X written by Andreas Dillmann and published by Springer. This book was released on 2016-03-28 with total page 855 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents contributions to the 19th biannual symposium of the German Aerospace Aerodynamics Association (STAB) and the German Society for Aeronautics and Astronautics (DGLR). The individual chapters reflect ongoing research conducted by the STAB members in the field of numerical and experimental fluid mechanics and aerodynamics, mainly for (but not limited to) aerospace applications, and cover both nationally and EC-funded projects. Special emphasis is given to collaborative research projects conducted by German scientists and engineers from universities, research-establishments and industries. By addressing a number of cutting-edge applications, together with the relevant physical and mathematics fundamentals, the book provides readers with a comprehensive overview of the current research work in the field. Though the book’s primary emphasis is on the aerospace context, it also addresses further important applications, e.g. in ground transportation and energy.
Download or read book Progress in Propulsion Physics written by Luigi T. DeLuca and published by . This book was released on 2012 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt: La péface indique : "EUCASS (European Conference for Aero-Space Sciences) is a scientific association at the service of research scientists, engineers, and decision makers active in aeronautical and space sciences. EUCASS, which is an international nonprofit association under the Belgian law, addresses all topics of interest to aerospace, from research challenges to long-term programmes and prospective. It organizes regular conferences, workshops, and meetings. Its goal is to attract the best specialists from Europe and elsewhere, and to create a commonwealth of interest and challenges where in-formation and ideas circulate freely and swiftly, where the currently scattered European knowledge is exchanged much faster and cross-fertilised. EUCASS is the cradle that nurtures a friendly and lively community spirit among all players. It started its activities in 2005 by organizing the first-ever European conference in Moscow, followed at a biennial rate in Brussels and Versailles. In order to contribute to the dissemination of scientific knowledge, we have launched this EUCASS Book Series, the first and second volumes of which were dedicated to Propulsion Physics and presented a selection of the lectures given in Brussels in July 2007. EUCASS is organized in several permanent Technical Committees (TC). One of them is the Flight Physics TC. Within the broad EUCASS framework, the specificc purpose of the Flight Physics TC is to promote the technology, sciences, and arts of Flight physics and to help those engaged in these pursuits to develop their skills and those of their students. This third volume of the EUCASS Book Series on Advances in Aerospace Sciences is dedicated to Flight Physics. It comprises a selected collection of 43 papers presented at the 3rd European Conference for Aerospace Sciences held in Versailles, France, July 06-10, 2009. The current volume is the result of a long review process. About 1/3 of the total number of papers accepted for presentation at the conference was later selected by the volume editors, then edited by an international body of peer reviewers. The volume includes six chapters covering experimental, theoretical and numerical aspects of the fight physics: Chapter One Aerodynamics, Chapter Two Shock Interaction, Chapter Three High Enthalphy Flows, Chapter Four Heat Transfer, Chapter Five Aeroacoustics, Chapter Six Flow Control. To easily identify the material of interest, the reader is invited to consult the brief paper summaries compiled at the start of each chapter."
Download or read book Three Dimensional Attached Viscous Flow written by Ernst Heinrich Hirschel and published by Springer Science & Business Media. This book was released on 2013-10-29 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: Viscous flow is treated usually in the frame of boundary-layer theory and as two-dimensional flow. Books on boundary layers give at most the describing equations for three-dimensional boundary layers, and solutions often only for some special cases. This book provides basic principles and theoretical foundations regarding three-dimensional attached viscous flow. Emphasis is put on general three-dimensional attached viscous flows and not on three-dimensional boundary layers. This wider scope is necessary in view of the theoretical and practical problems to be mastered in practice. The topics are weak, strong, and global interaction, the locality principle, properties of three-dimensional viscous flow, thermal surface effects, characteristic properties, wall compatibility conditions, connections between inviscid and viscous flow, flow topology, quasi-one- and two-dimensional flows, laminar-turbulent transition and turbulence. Though the primary flight speed range is that of civil air transport vehicles, flows past other flying vehicles up to hypersonic speeds are also considered. Emphasis is put on general three-dimensional attached viscous flows and not on three-dimensional boundary layers, as this wider scope is necessary in view of the theoretical and practical problems that have to be overcome in practice. The specific topics covered include weak, strong, and global interaction; the locality principle; properties of three-dimensional viscous flows; thermal surface effects; characteristic properties; wall compatibility conditions; connections between inviscid and viscous flows; flow topology; quasi-one- and two-dimensional flows; laminar-turbulent transition; and turbulence. Detailed discussions of examples illustrate these topics and the relevant phenomena encountered in three-dimensional viscous flows. The full governing equations, reference-temperature relations for qualitative considerations and estimations of flow properties, and coordinates for fuselages and wings are also provided. Sample problems with solutions allow readers to test their understanding.
Download or read book Advances in Hypersonics written by Bertin and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: These three volumes entitled Advances in Hypersonics contain the Proceedings of the Second and Third Joint US/Europe Short Course in Hypersonics which took place in Colorado Springs and Aachen. The Second Course was organized at the US Air Force Academy, USA in January 1989 and the Third Course at Aachen, Germany in October 1990. The main idea of these Courses was to present to chemists, com puter scientists, engineers, experimentalists, mathematicians, and physicists state of the art lectures in scientific and technical dis ciplines including mathematical modeling, computational methods, and experimental measurements necessary to define the aerothermo dynamic environments for space vehicles such as the US Orbiter or the European Hermes flying at hypersonic speeds. The subjects can be grouped into the following areas: Phys ical environments, configuration requirements, propulsion systems (including airbreathing systems), experimental methods for external and internal flow, theoretical and numerical methods. Since hyper sonic flight requires highly integrated systems, the Short Courses not only aimed to give in-depth analysis of hypersonic research and technology but also tried to broaden the view of attendees to give them the ability to understand the complex problem of hypersonic flight. Most of the participants in the Short Courses prepared a docu ment based on their presentation for reproduction in the three vol umes. Some authors spent considerable time and energy going well beyond their oral presentation to provide a quality assessment of the state of the art in their area of expertise as of 1989 and 1991.
Download or read book Aerothermodynamik written by Herbert Oertel and published by . This book was released on 1994 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Hypersonic Test Facilities written by Frank K. Lu and published by AIAA. This book was released on 2002 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thermal Design of Aeroassisted Orbital Transfer Vehicles written by H. F. Nelson and published by . This book was released on 1985 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Hypersonics written by BALLMAN and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: These three volumes entitled Advances in Hypersonics contain the Proceedings of the Second and Third Joint US/Europe Short Course in Hypersonics which took place in Colorado Springs and Aachen. The Second Course was organized at the US Air Force Academy, USA in January 1989 and the Third Course at Aachen, Germany in October 1990. The main idea of these Courses was to present to chemists, com puter scientists, engineers, experimentalists, mathematicians, and physicists state of the art lectures in scientific and technical dis ciplines including mathematical modeling, computational methods, and experimental measurements necessary to define the aerothermo dynamic environments for space vehicles such as the US Orbiter or the European Hermes flying at hypersonic speeds. The subjects can be grouped into the following areas: Phys ical environments, configuration requirements, propulsion systems (including airbreathing systems), experimental methods for external and internal flow, theoretical and numerical methods. Since hyper sonic flight requires highly integrated systems, the Short Courses not only aimed to give in-depth analysis of hypersonic research and technology but also tried to broaden the view of attendees to give them the ability to understand the complex problem of hypersonic flight. Most of the participants in the Short Courses prepared a docu ment based on their presentation for reproduction in the three vol umes. Some authors spent considerable time and energy going well beyond their oral presentation to provide a quality assessment of the state of the art in their area of expertise as of 1989 and 1991.
Download or read book Reusable Space Transportation Systems written by Heribert Kuczera and published by Springer. This book was released on 2011-01-22 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Brings together for the first time details of the technology available and being developed to provide totally reusable launch vehicles for the future exploitation and exploration of space.
