Download or read book Towards Understanding the Mechanism of Receptivity and Bypass Dynamics in Laminar Boundary Layers written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-09-17 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three problems concerning laminar-turbulent transition are addressed by solving a series of initial value problems. The first problem is the calculation of resonance within the continuous spectrum of the Blasius boundary layer. The second is calculation of the growth of Tollmien-Schlichting waves that are a direct result of disturbances that only lie outside of the boundary layer. And, the third problem is the calculation of non-parallel effects. Together, these problems represent a unified approach to the study of freestream disturbance effects that could lead to transition. Solutions to the temporal, initial-value problem with an inhomogeneous forcing term imposed upon the flow is sought. By solving a series of problems, it is shown that: A transient disturbance lying completely outside of the boundary layer can lead to the growth of an unstable Tollmien-Schlichting wave. A resonance with the continuous spectrum leads to strong amplification that may provide a mechanism for bypass transition once nonlinear effects are considered. A disturbance with a very weak unstable Tollmien-Schlichting wave can lead to a much stronger Tollmien-Schlichting wave downstream, if the original disturbance has a significant portion of its energy in the continuum modes.Lasseigne, D. G. and Criminale, W. O. and Joslin, R. D. and Jackson, T. L.Langley Research CenterBOUNDARY LAYER TRANSITION; LAMINAR BOUNDARY LAYER; TURBULENT BOUNDARY LAYER; BLASIUS FLOW; TURBULENT FLOW; TOLLMIEN-SCHLICHTING WAVES; BOUNDARY VALUE PROBLEMS; CONTINUOUS SPECTRA; FREE FLOW; COMPUTATIONAL FLUID DYNAMICS; DIRECT NUMERICAL SIMULATION; THREE DIMENSIONAL MODELS; EQUATIONS OF MOTION; LINEAR SYSTEMS
Download or read book Towards Understanding the Mechanism of Receptivity and Bypass Dynamics in Laminar Boundary Layers written by D. G. Lasseigne and published by . This book was released on 1999 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theory and Computation of Hydrodynamic Stability written by W. O. Criminale and published by Cambridge University Press. This book was released on 2003-10-23 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of hydrodynamic stability is fundamental to many subjects, ranging from geophysics and meteorology through to engineering design. This treatise covers both classical and modern aspects of the subject, systematically developing it from the simplest physical problems, then progressing chapter by chapter to the most complex, considering linear and nonlinear situations, and analysing temporal and spatial stability. The authors examine each problem both analytically and numerically: many chapters end with an appendix outlining relevant numerical techniques. All relevant fluid flows are treated, including those where the fluid may be compressible, or those from geophysics, or those that require salient geometries for description. Details of initial-value problems are explored equally with those of stability. As a result, the early transient period as well as the asymptotic fate for perturbations for a flow can be assessed. The text is enriched with many exercises, copious illustrations and an extensive bibliography and the result is a book that can be used with courses on hydrodynamic stability or as an authoritative reference for researchers.
Download or read book NASA Langley Scientific and Technical Information Output 1999 written by and published by . This book was released on 2000 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Boundary Layer Receptivity Mechanisms Relevant to Laminar Flow Control written by Meelan Choudhari and published by . This book was released on 1990 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Monthly Catalog of United States Government Publications written by and published by . This book was released on 2000 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Viscous Drag Reduction in Boundary Layers written by and published by AIAA. This book was released on 1990 with total page 542 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1993 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recent Results in Laminar Turbulent Transition written by Siegfried Wagner and published by Springer Science & Business Media. This book was released on 2013-06-05 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 24 papers presented at the international concluding colloquium of the German priority programme (DFG-Verbundschwerpunktprogramm) "Transition", held in April 2002 in Stuttgart. The unique and successful programme ran six years, starting April 1996, and was sponsored mainly by the Deutsche Forschungsgemeinschaft, DFG, but also by the Deutsches Zentrum für Luft-und Raumfahrt, DLR, the Physikalisch-Technische Bundesanstalt Braunschweig, PTB, and Airbus Deutschland. The papers summarise the results of the programme and cover transition mechanisms, transition prediction, transition control, natural transition and measurement techniques, transition - turbulence - separation, and visualisation issues. Three invited papers are devoted to mechanisms of turbulence production, to a general framework of stability, receptivity and control, and a forcing model for receptivity analysis. Almost every transition topic arising in subsonic and transonic flow is covered.
Download or read book Laminar Turbulent Transition written by Ryoji Kobayashi and published by Springer. This book was released on 1995-07-14 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: The International Union of Theoretical and Applied Mechanics (IUTAM) decided in 1992 to sponsor the fourth Symposium on Laminar-Turbulent Transition, Sendai/Japan, 1994. The objectives of the present Symposium were to deepen the fundamental knowledge of stability and laminar turbulent transition in three-dimensional and compressible flows and to contribute to recent developing technologies in the field. This Symposium followed the three previous IUTAM-Symposia (Stuttgart 1979, Novosibirsk 1984 and Toulouse 1989). The Scientific Committee selected two keynote lectures and 62 technical papers. The Symposium was held on the 5th to 9th of September, 1994, at the Sendai International Center in Sendai. The participants were 82 scientists from 10 countries. The keynote lectures have critically reviewed recent development of researches concerning the laminar-to-turbulent transition phenomena from the fundamental and the application aspects. Many papers presented were concerned about the detailed mechanism of the boundary layer transition (receptivity, secondary instability, turbulent spot and bypass transition). Particular emphasis was further placed on the transition of three-dimensional boundary layers on rotation systems and on swept wings. Attention was also given to compressible hypersonic flows.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanism of Hairpin Vortex Formation by Liutex written by Yifei Yu and published by Springer Nature. This book was released on with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 30th AIAA Fluid Dynamics Conference written by and published by . This book was released on 1999 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Instabilities of Flows and Transition to Turbulence written by Tapan K. Sengupta and published by CRC Press. This book was released on 2012-04-24 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addressing classical material as well as new perspectives, Instabilities of Flows and Transition to Turbulence presents a concise, up-to-date treatment of theory and applications of viscous flow instability. It covers materials from classical instability to contemporary research areas including bluff body flow instability, mixed convection flows, and application areas of aerospace and other branches of engineering. Transforms and perturbation techniques are used to link linear instability with receptivity of flows, as developed by the author. The book: Provides complete coverage of transition concepts, including receptivity and flow instability Introduces linear receptivity using bi-lateral Fourier-Laplace transform techniques Presents natural laminar flow (NLF) airfoil analysis and design as a practical application of classical and bypass transition Distinguishes strictly between instability and receptivity, which leads to identification of wall- and free stream-modes Describes energy-based receptivity theory for the description of bypass transitions Instabilities of Flows and Transition to Turbulence has evolved into an account of the personal research interests of the author over the years. A conscious effort has been made to keep the treatment at an elementary level requiring rudimentary knowledge of calculus, the Fourier-Laplace transform, and complex analysis. The book is equally amenable to undergraduate students, as well as researchers in the field.
Download or read book Experimental Study of Laminar Boundary Layer Receptivity to a Traveling Pressure Field written by J. M. Kendall and published by . This book was released on 1987 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
