Download or read book Stability of Time Dependent and Spatially Varying Flows written by D.L. Dwoyer and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is the collection of papers presented at the workshop on 'The Stability of Spatially Varying and Time Dependent Flows" sponsored by the Institute for Computer Applications in Science and Engineering (lCASE) and NASA Langley Research Center (LaRC) during August 19- 23, 1985. The purpose of this workshop was to bring together some of the experts in the field for an exchange of ideas to update the current status of knowledge and to help identify trends for future research. Among the invited speakers were D.M. Bushnell, M. Goldstein, P. Hall, Th. Herbert, R.E. Kelly, L. Mack, A.H. Nayfeh, F.T. Smith, and C. von Kerczek. The contributed papers were by A. Bayliss, R. Bodonyi, S. Cowley, C. Grosch, S. Lekoudis, P. Monkewitz, A. Patera, and C. Streett. In the first article, Bushnell provides a historical background on laminar flow control (LFC) research and summarizes the crucial role played by stability theory in LFC system design. He also identifies problem areas in stability theory requiring further research from the view-point of ap plications to LFC design. It is an excellent article for theoreticians looking for some down-to-earth applications of stability theory.
Download or read book The Origin of Turbulence in Near Wall Flows written by A.V. Boiko and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Origin of Species Charles Darwin The origin of turbulence in fluids is a long-standing problem and has been the focus of research for decades due to its great importance in a variety of engineering applications. Furthermore, the study of the origin of turbulence is part of the fundamental physical problem of turbulence description and the philosophical problem of determinism and chaos. At the end of the nineteenth century, Reynolds and Rayleigh conjectured that the reason of the transition of laminar flow to the 'sinuous' state is in stability which results in amplification of wavy disturbances and breakdown of the laminar regime. Heisenberg (1924) was the founder of linear hydrody namic stability theory. The first calculations of boundary layer stability were fulfilled in pioneer works of Tollmien (1929) and Schlichting (1932, 1933). Later Taylor (1936) hypothesized that the transition to turbulence is initi ated by free-stream oscillations inducing local separations near wall. Up to the 1940s, skepticism of the stability theory predominated, in particular due to the experimental results of Dryden (1934, 1936). Only the experiments of Schubauer and Skramstad (1948) revealed the determining role of insta bility waves in the transition. Now it is well established that the transition to turbulence in shear flows at small and moderate levels of environmental disturbances occurs through development of instability waves in the initial laminar flow. In Chapter 1 we start with the fundamentals of stability theory, employing results of the early studies and recent advances.
Download or read book Ordered and Turbulent Patterns in Taylor Couette Flow written by C. David Andereck and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 351 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seldom does a physical system, particularly one as apparently simple as the flow of a Newtonian fluid between concentric rotating cylinders, retain the interest of scientists, applied mathematicians and engineers for very long. Yet, as this volume goes to press it has been nearly 70 years since G. I. Taylor's outstanding experimental and theoretical study of the linear stability of this flow was published, and a century since the first experiments were performed on rotating cylinder viscometers. Since then, the study of this system has progressed enormously, but new features of the flow patterns are still being uncovered. Interesting variations on the basic system abound. Connections with open flows are being made. More complex fluids are used in some experiments. The vigor of the research going on in this particular example of nonequilibrium systems was very apparent at the NATO Advanced Research Workshop on "Ordered and Turbulent Patterns in Taylor Couette Flow," held in Columbus, Ohio, USA May 22-24, 1991. A primary goal of this ARW was to bring together those interested in pattern formation in the classic Taylor Couette problem with those looking at variations on the basic system and with those interested in related systems, in order to better define the interesting areas for the future, the open questions, and the features common (and not common) to closed and open systems. This volume contains many of the contributions presented during the workshop.
Download or read book Direct and Large Eddy Simulation of Turbulence written by NA Schumann and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains papers presented to a EUROMECH-Colloquium held in Munich, September 30 to October 2, 1985. The Colloquium is number 199 in a series of colloquia inaugurated by the European Mechanics Committee. The meeting was jointly organized by the 'Lehrstuhl fur Stromungsmechanik' at the 'Technische Universitat Munchen' and the 'Institut fur Physik der Atmosphare' of the 'Deutsche Forschungs- und Versuchsanstalt fur Luft- und Raumfahrt' (DFVLR) in Oberpfaffenhofen. 'Direct' and 'large eddy simulation' are terms which denote two closely con nected methods of turbulence research. In a 'direct simulation' (DS), turbu lent motion is simulated by numerically integrating the Navier-Stokes equations in three-dimensional space and as a function of time. Besides ini tial and boundary conditions no physical simplifications are involved. Com puter resources limit the resolution in time and space, though simulations with an order of one million discrete points in space are feasible. The simu lated flow fields can be considered as true realizations of turbulent flow fields and analysed to answer questions on the basic behaviour of turbulence. Direct simulations are valid as long as all the excited scales remain within the band of resolved scales. This means that viscosity must be strong enough to damp out the not resolved scales or the simulation is restricted to a lim ited integration-time interval only. In summary, DS provides a tool to investigate turbulent motions from first principles at least for a finite band of scales.
Download or read book IUTAM Symposium on Mechanics of Passive and Active Flow Control written by G.E.A. Meier and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: The call for papers for the rUTAM-Symposium on Mechanics of Passive and Active Flow Control brought an overwhelming response of applications for contributions. Fi nally 12 invited lectures, 48 papers and 23 posters were selected by thc Scientific Com mittee to be presented in the conference. 58 papers are published in this volume. Due to the limited number of pages available, poster presentations could not be considered for publication. The editors would like to thank all the members of the Scientific Committee for their very valuable assistance. The papers presented at the rUT AM Symposium were classified under three groups de voted to • Passive Control Methods, • Active Control Methods and • Control Concepts. This was done to contrast at first between the passive techniques where the control power is mainly supplied by the flow itself and the active techniques where the power is pro vided by external sources; the third group was devoted to control concepts for presenting methods of control theory and new techniques of flow control.
Download or read book Laminar Turbulent Transition written by H.F. Fasel and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 703 pages. Available in PDF, EPUB and Kindle. Book excerpt: The origins of turbulent flow and the transition from laminar to turbulent flow are among the most important unsolved problems of fluid mechanics and aerodynamics. Besides being a fundamental question of fluid mechanics, there are any number of applications for information regarding transition location and the details of the subsequent turbulent flow. The JUT AM Symposium on Laminar-Turbulent Transition, co-hosted by Arizona State University and the University of Arizona, was held in Sedona, Arizona. Although four previous JUT AM Symposia bear the same appellation (Stuttgart 1979, Novosibirsk 1984, Toulouse 1989, and Sendai 1994) the topics that were emphasized at each were different and reflect the evolving nature of our understanding of the transition process. The major contributions of Stuttgart 1979 centered on nonlinear behavior and later stages of transition in two-dimensional boundary layers. Stability of closed systems was also included with Taylor vortices in different geometries. The topics of Novosibirsk 1984 shifted to resonant wave interactions and secondary instabilities in boundary layers. Pipe- and channel-flow transition were discussed as model problems for the boundary layer. Investigations of free shear layers were presented and a heavy dose of supersonic papers appeared for the first time. The character of Toulouse 1989 was also different in that 3-D boundary layers, numerical simulations, streamwise vortices, and foundation papers on receptivity were presented. Sendai 1994 saw a number of papers on swept wings and 3-D boundary layers. Numerical simulations attacked a broader range of problems.
Download or read book Physics of Transitional Shear Flows written by Andrey V. Boiko and published by Springer Science & Business Media. This book was released on 2011-09-15 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt: Starting from fundamentals of classical stability theory, an overview is given of the transition phenomena in subsonic, wall-bounded shear flows. At first, the consideration focuses on elementary small-amplitude velocity perturbations of laminar shear layers, i.e. instability waves, in the simplest canonical configurations of a plane channel flow and a flat-plate boundary layer. Then the linear stability problem is expanded to include the effects of pressure gradients, flow curvature, boundary-layer separation, wall compliance, etc. related to applications. Beyond the amplification of instability waves is the non-modal growth of local stationary and non-stationary shear flow perturbations which are discussed as well. The volume continues with the key aspect of the transition process, that is, receptivity of convectively unstable shear layers to external perturbations, summarizing main paths of the excitation of laminar flow disturbances. The remainder of the book addresses the instability phenomena found at late stages of transition. These include secondary instabilities and nonlinear features of boundary-layer perturbations that lead to the final breakdown to turbulence. Thus, the reader is provided with a step-by-step approach that covers the milestones and recent advances in the laminar-turbulent transition. Special aspects of instability and transition are discussed through the book and are intended for research scientists, while the main target of the book is the student in the fundamentals of fluid mechanics. Computational guides, recommended exercises, and PowerPoint multimedia notes based on results of real scientific experiments supplement the monograph. These are especially helpful for the neophyte to obtain a solid foundation in hydrodynamic stability. To access the supplementary material go to extras.springer.com and type in the ISBN for this volume.
Download or read book Flow Control written by Thomas C. Corke and published by Cambridge University Press. This book was released on 2024-04-11 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive treatment of passive and active flow control in fluid dynamics, with an emphasis on utilizing fluid instabilities for enhancing control performance. Examples are given from a wide range of technologically important flow fields occurring in aerospace applications, from low-subsonic to hypersonic Mach numbers. This essential book can be used for both research and teaching on the topics of fluid instabilities, fluid measurement and flow actuator techniques, and problem sets are provided at the end of each chapter to reinforce key concepts and further extend readers' understanding of the field. The solutions manual is available as a online resource for instructors. The text is well suited for both graduate students in fluid dynamics and for practising engineers in the aerodynamics design field.
Download or read book IUTAM Symposium on Nonlinear Instability and Transition in Three Dimensional Boundary Layers written by Peter W. Duck and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most fluid flows of practical importance are fully three-dimensional, so the non-linear instability properties of three-dimensional flows are of particular interest. In some cases the three-dimensionality may have been caused by a finite amplitude disturbance whilst, more usually, the unperturbed state is three-dimensional. Practical applications where transition is thought to be associated with non-linearity in a three- dimensional flow arise, for example, in aerodynamics (swept wings, engine nacelles, etc.), turbines and aortic blood flow. Here inviscid `cross-flow' disturbances as well as Tollmien-Schlichting and Görtler vortices can all occur simultaneously and their mutual non-linear behaviour must be understood if transition is to be predicted. The non-linear interactions are so complex that usually fully numerical or combined asymptotic/numerical methods must be used. Moreover, in view of the complexity of the instability processes, there is also a growing need for detailed and accurate experimental information. Carefully conducted tests allow us to identify those elements of a particular problem which are dominant. This assists in both the formulation of a relevant theoretical problem and the subsequent physical validation of predictions. It should be noted that the demands made upon the skills of the experimentalist are high and that the tests can be extremely sophisticated - often making use of the latest developments in flow diagnostic techniques, automated high speed data gathering, data analysis, fast processing and presentation.
Download or read book Instability and Transition written by M.Y. Hussaini and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: These two volumes contain the proceedings of the workshop on the Institute for Computer Instability and Transition, sponsored by Applications in Science and Engineering (ICASE) and the Langley Research Center (LaRC), during May 15 to June 9, 1989. The work shop coincided with the initiation of a new, focused research pro gram on instability and transition at LaRC. The objectives of the workshop were to (i) expose the academic community to current technologically important issues of instability and transition in shear flows over the entire speed range, (ii) acquaint the academic com munity with the unique combination of theoretical, computational and experimental capabilities at LaRC and foster interaction with these facilities, (iii) review current state-of-the-art and propose fu ture directions for instability and transition research, (iv) accelerate progress in elucidating basic understanding of transition phenomena and in transferring this knowledge into improved design methodolo gies through improved transition modeling, and (v) establish mech anisms for continued interaction. The objectives (i) to (iii) were of course immediately met. It is still premature to assess whether ob jectives (iv) and (v) are achieved. The workshop program consisted of tutorials, research presenta tions, panel discussions, experimental and computational demonstra tions, and collaborative projects.
Download or read book Unsteady Combustor Physics written by Tim C. Lieuwen and published by Cambridge University Press. This book was released on 2021-10-21 with total page 533 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explore a unified treatment of the dynamics of combustor systems, including acoustics, fluid mechanics, and combustion in a single rigorous text. This updated new edition features an expansion of data and experimental material, updates the coverage of flow stability, and enhanced treatment of flame dynamics. Addresses system dynamics of clean energy and propulsion systems used in low emissions systems. Synthesizing the fields of fluid mechanics and combustion into a coherent understanding of the intrinsically unsteady processes in combustors. This is a perfect reference for engineers and researchers in fluid mechanics, combustion, and clean energy.
Download or read book Laminar Turbulent Transition written by D. Arnal and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 706 pages. Available in PDF, EPUB and Kindle. Book excerpt: The subject of laminar-turbulent transition is of considerable practical importance and has a wide range of engineering applications. For this reason, the International Union of Applied Mechanics decided to sponsor a third Symposium on "Laminar-Turbulent Transition", which would be organised by the ONERA Toulouse Research Center and held at "Ecole Nationale Superieure de l'Aeronautique et de l'Espace" in 1989. It was supposed that like the two previous IUTAM Symposia (Stuttgart 1979 and Novosibirsk 1984) the symposium would be devoted to experimental of laminar-turbulent transition In fluids, i.e. the and theoretical studies physical problem of transition and mathematical modelling in shear flows. The contributed papers were selected by the Scientific Committee from extended abstracts. The larger number of highly qualified papers submitted for presentation led us to include in the program poster sessions, which could be held during morning, lunch and afternoon breaks, and to take the decision that the symposium should last five days (from Monday 11 to Friday 15 September). An excursion on Wednesday offering a well deserved rest and the occasion of new personal exchanges between the participants seems to have been appreciated by all. The symposium consisted of 8 invited lectures and 62 contributed pa pers presented either on oral or poster sessions.
Download or read book Transonic Symposium Theory Application and Experiment written by and published by . This book was released on 1989 with total page 964 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrodynamic Instability and Transition to Turbulence written by Akiva M. Yaglom and published by Springer Science & Business Media. This book was released on 2012-12-18 with total page 611 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a complete revision of the part of Monin & Yaglom's famous two-volume work "Statistical Fluid Mechanics: Mechanics of Turbulence" that deals with the theory of laminar-flow instability and transition to turbulence. It includes the considerable advances in the subject that have been made in the last 15 years or so. It is intended as a textbook for advanced graduate courses and as a reference for research students and professional research workers. The first two Chapters are an introduction to the mathematics, and the experimental results, for the instability of laminar (or inviscid) flows to infinitesimal (in practice "small") disturbances. The third Chapter develops this linear theory in more detail and describes its application to particular problems. Chapters 4 and 5 deal with instability to finite-amplitude disturbances: much of the material has previously been available only in research papers.
Download or read book Instability Transition and Turbulence written by M.Y. Hussaini and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the Workshop on In stability, Transition and Turbulence, sponsored by the Institute for Computer Applications in Science and Engineering (ICASE) and the NASA Langley Research Center (LaRC), during July 8 to August 2, 1991. This is the second workshop in the series on the subject. The first was held in 1989, and its proceedings were published by Springer-Verlag under the title "Instability and Transition" edited by M. Y. Hussaini and R. G. Voigt. The objectives of these work shops are to i) expose the academic community to current technologically im portant issues of transition and turbulence in shear flows over the entire speed range, ii) acquaint the academic community with the unique combination of theoretical, computational and experimental capabilities at LaRC and foster interaction with these capabilities, and iii) accelerate progress in elucidating the fundamental phenomena of transition and turbulence, leading to improved transition and turbulence modeling in design methodologies. The research areas covered in these proceedings include receptiv ity and roughness, nonlinear theories of transition, numerical simu lation of spatially evolving flows, modelling of transitional and fully turbulent flows as well as some experiments on instability and tran sition. In addition a one-day mini-symposium was held to discuss 1 recent and planned experiments on turbulent flow over a backward facing step.
Download or read book Activities of the Institute for Computer Applications in Science and Engineering written by and published by . This book was released on 1985 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct and Large Eddy Simulation I written by Peter R. Voke and published by Springer Science & Business Media. This book was released on 1994-10-31 with total page 454 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is a truism that turbulence is an unsolved problem, whether in scientific, engin eering or geophysical terms. It is strange that this remains largely the case even though we now know how to solve directly, with the help of sufficiently large and powerful computers, accurate approximations to the equations that govern tur bulent flows. The problem lies not with our numerical approximations but with the size of the computational task and the complexity of the solutions we gen erate, which match the complexity of real turbulence precisely in so far as the computations mimic the real flows. The fact that we can now solve some turbu lence in this limited sense is nevertheless an enormous step towards the goal of full understanding. Direct and large-eddy simulations are these numerical solutions of turbulence. They reproduce with remarkable fidelity the statistical, structural and dynamical properties of physical turbulent and transitional flows, though since the simula tions are necessarily time-dependent and three-dimensional they demand the most advanced computer resources at our disposal. The numerical techniques vary from accurate spectral methods and high-order finite differences to simple finite-volume algorithms derived on the principle of embedding fundamental conservation prop erties in the numerical operations. Genuine direct simulations resolve all the fluid motions fully, and require the highest practical accuracy in their numerical and temporal discretisation. Such simulations have the virtue of great fidelity when carried out carefully, and repre sent a most powerful tool for investigating the processes of transition to turbulence.
