The Growth of Goertler Vortices in Compressible Boundary Layers
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Publisher :
Page : 32 pages
File Size : 10,96 MB
Release : 1987
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ISBN :
Author :
Publisher :
Page : 32 pages
File Size : 10,96 MB
Release : 1987
Category :
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Author : Jie Ren
Publisher : Springer
Page : 110 pages
File Size : 31,25 MB
Release : 2017-10-27
Category : Technology & Engineering
ISBN : 9811068321
This thesis first reveals the mechanism of Görtler instabilities and then demonstrates how transitions at hypersonic flows can be effectively controlled (either promoted or suppressed) with Görtler or Klebanoff modes. It focuses on understanding and controlling flow transitions from mild laminar to fully turbulent flows at high speeds—aspects that have become crucial at the dawn of an incredible era, in which hypersonic vehicles are becoming available. Once this occurs, it will be possible to travel from Beijing to Los Angeles within just 2 hours, and we will all live in a genuinely global village—and not just virtually, but physically. Görtler instabilities have often been used to promote flow transition in hypersonic vehicles. However, how Görtler instabilities are excited and how they evolve in hypersonic flows are questions that have yet to be answered.
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
Page : 66 pages
File Size : 12,75 MB
Release : 2018-07-08
Category :
ISBN : 9781722420703
Goertler vortices are thought to be the cause of transition in many fluid flows of practical importance. A review of the different stages of vortex growth is given. In the linear regime, nonparallel effects completely govern this growth, and parallel flow theories do not capture the essential features of the development of the vortices. A detailed comparison between the parallel and nonparallel theories is given and it is shown that at small vortex wavelengths, the parallel flow theories have some validity; otherwise nonparallel effects are dominant. New results for the receptivity problem for Goertler vortices are given; in particular vortices induced by free stream perturbations impinging on the leading edge of the walls are considered. It is found that the most dangerous mode of this type can be isolated and it's neutral curve is determined. This curve agrees very closely with the available experimental data. A discussion of the different regimes of growth of nonlinear vortices is also given. Again it is shown that, unless the vortex wavelength is small, nonparallel effects are dominant. Some new results for nonlinear vortices of 0(1) wavelengths are given and compared to experimental observations. Hall, Philip Unspecified Center...
Author :
Publisher :
Page : 562 pages
File Size : 12,20 MB
Release : 1992
Category : Aeronautics
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Publisher :
Page : 1346 pages
File Size : 39,66 MB
Release : 1991-05
Category : Government publications
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Publisher :
Page : 780 pages
File Size : 49,83 MB
Release : 1991
Category : Government publications
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Author : Thomas B. Gatski
Publisher : Springer Science & Business Media
Page : 609 pages
File Size : 48,96 MB
Release : 2012-12-06
Category : Science
ISBN : 1461227925
This book contains contributions by former students, colleagues and friends of Professor John L. Lumley, on the occasion of his 60th birthday, in recognition of his enormous impact on the advancement of turbulence research. A variety of experimental, computational and theoretical topics, including turbulence modeling, direct numerical simulations, compressible turbulence, turbulent shear flows, coherent structures and the Proper Orthogonal Decomposition are contained herein. The diversity and scope of these contributions are further acknowledgment of John Lumley's wide ranging influence in the field of turbulence. The large number of contributions by the authors, many of whom were participants in The Lumley Symposium: Recent Developments in Turbulence (held at ICASE, NASA Langley Research Center on November 12 & 13, 1990), has presented us with the unique opportu nity to select a few numerical and theoretical papers for inclusion in the journal Theoretical and Computational Fluid Dynamics for which Professor Lumley serves as Editor. Extended Abstracts of these pa pers are included in this volume and are appropriately marked. The special issue of TCFD will appear this year and will serve as an additional tribute to John Lumley. As is usually the case, the efforts of others have significantly eased our tasks. We would like to express our deep appreciation to Drs. R.
Author : D. Arnal
Publisher : Springer Science & Business Media
Page : 706 pages
File Size : 16,93 MB
Release : 2012-12-06
Category : Science
ISBN : 3642841031
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.
Author :
Publisher :
Page : 340 pages
File Size : 25,40 MB
Release : 1986
Category : Fluid dynamics
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Author : Daniel N. Riahi
Publisher : World Scientific
Page : 208 pages
File Size : 15,49 MB
Release : 1996
Category : Science
ISBN : 9789810223083
Hydrodynamic stability is of fundamental importance in the mechanics of fluids and is mainly concerned with the problem of the transition to turbulence. This book is devoted to publication of original research papers, research-expository and survey articles with an emphasis on unsolved problems and open questions in the mathematical modeling and computational aspects of hydrodynamic stability. Review chapters on the mathematical modeling and numerical simulation aspects of hydrodynamic stability, the physical background, and the limitations of the modeling and simulation procedures, due to particular mathematical or computational methods used, are included. This book will be appropriate for use in research and in research-related courses on the subject. It includes chapters on bifurcations in fluid systems, flow patterns, channel flows, non-parallel shear flows, thin-film flows, strong viscous shear flows, Gortler vortices, bifurcations in convection, wavy film flows and boundary layers.