Download or read book Stability of a Vortex Sheet in Non equilibrium Flows written by K. C. Wang and published by . This book was released on 1960 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this report the stability of a plane vortex sheet between two uniform streams with respect to small disturbances is examined when the two media are dissociating diatomic gases such as oxygen and nitrogen. For the equilibrium and frozen cases, it is found that the eigenvalue equation is formally identical with that of the conventional case, and the stability is decreased due to the dissociation. For the non-equilibrium case, the eigenvalue equation is a complex one and depends on the wave number of the disturbances, the vortex sheet is shown to be always unstable. Included also is a discussion of the stability of a vortex sheet between two equal but opposite steady streams from the consideration of pressure distribution.
Download or read book Stability of a Plane Vortex Sheet Between Gases Exchanging Heat by Radiation written by Burton E. Eno and published by . This book was released on 1971 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Abstract Bulletin written by Defense Documentation Center (U.S.) and published by . This book was released on 1961-04 with total page 1746 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Equilibrium and Stability in Vortex and Wave Flows written by Paolo Luzzatto Fegiz and published by . This book was released on 2011 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation focuses on the development of theoretical and numerical methodologies to study equilibrium and stability in conservative fluid flows. These techniques include: a bifurcation-diagram approach to obtain the stability properties of families of steady flows; a theory of Hamiltonian resonance for vortex arrays; an efficient numerical method for computing vortices with arbitrary symmetry; and a variational principle for compressible, barotropic or baroclinic flows. We employ these theoretical and numerical approaches to obtain new results regarding the structure and stability of several fundamental vortex and wave flows. The applications that we examine involve simple representations of fundamental fluid problems, which may be regarded as prototypical of flows associated with transport and mixing in the ocean and in the atmosphere, with aquatic animal propulsion, and with the dynamics of vortices in quantum condensates. We address two issues affecting the use of a variational argument to determine stability of families of steady flows. By building on ideas from bifurcation theory, we link turning points in a velocity-impulse diagram to gains or losses of stability. We introduce concepts from imperfection theory into these problems, enabling us to reveal hidden solution branches. The resulting methodology detects exchanges of stability through an "imperfect velocity-impulse" (IVI) diagram. We apply the IVI diagram approach to wide variety of vortex and wave flows. These examples include elliptical vortices, translating and ro- tating vortex pairs, single and double vortex rows, distributed vortices, as well as steep gravity waves. For a few of the flows considered, our work yields the first available stability boundaries. In addition, the IVI diagram methodology leads us to the discovery of several new families of steady flows, which exhibit lower symmetry. We next examine conditions for the development of an oscillatory instability in two-dimensional vortex arrays. By building on the theory of Krein signatures for Hamiltonian systems, we show that a resonant instability cannot occur for one or two vortices. To predict the onset of resonance for three or more vortices, we develop a simple approximate technique, which compares favorably with full analyses. In addition, we propose a simple technique to immediately check the accuracy of a detailed linear stability analysis. All of the uniform-vorticity equilibria analyzed in this dissertation were computed using a newly developed numerical approach. This methodology, which is based on Newton iteration, employs a new discretization to radically increases the efficiency of the calculation. In addition, we introduce a procedure to remove the degeneracies in the steady vorticity equation, thus ensuring convergence for general vortex configurations. Our method enables the computation, for the first time, of steady vortices that do not exhibit any geometric symmetry, in an unbounded flow. Finally, we re-examine the variational principle that underpins the IVI diagram stability approach. We show that this principle may be obtained, in a conceptually straightforward manner, by first considering the classical principle of virtual work. This link enables us to readily formulate generalizations to compressible, barotropic and baroclinic flows.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1974 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book U S Government Research Reports written by and published by . This book was released on 1963 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AFOSR written by United States. Air Force. Office of Scientific Research and published by . This book was released on 1950 with total page 1190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stability of a Plane Vortex Sheet Between Gases Exchanging Heat by Radiation written by Burton E. Eno and published by . This book was released on 1971 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 772 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stability Characteristics for Flows of the Vortex Sheet Type written by Y. T. Fung and published by . This book was released on 1982 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: The interfacial conditions for a cylindrical vortex sheet or a cylindrical fluid layer obtained earlier are examined further for the case of incompressible fluids. Only temporal perturbations are considered. Unlike the single role of destabilization played by the velocity in two-dimensional stratified flows or axisymmetric jet flows, the rotating velocity in vortex motions plays a dual role in flow stability. The radial velocity gradient generates tangential shear and the fluid rotation creates a centrifugal force field. While the former always destabilizes the flow, the latter can either stabilize or destabilize the flow depending upon whether the resultant force field is centrifugally stable or unstable. These characteristics are demonstrated by examining three general types of perturbations. We further show that deformations of the vortex sheet or the fluid layer affect the flow field in two ways: disturbing the total pressure field and perturbing the centrifugal force field created by the azimuthal components of the velocity and magnetic fields. The latter, even though it seems to be straightforward, has often been overlooked in previous analyses. It is shown that failure to consider such a perturbation to a stable centrifugal force field will lead to the improper destabilization of modes with smaller axial and azimuthal wave numbers.
Download or read book Hydrodynamic Stability of a Plane Vortex Sheet Between Thermally Radiating Dissimilar Gases written by Burton Edward Eno and published by . This book was released on 1971 with total page 286 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nonlinear Stability of Non stationary Cross flow Vortices in Compressible Boundary Layers written by and published by . This book was released on 1995 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Calculations of the Stability of Some Axisymmetric Flows Proposed as a Model of Vortex Breakdown written by Nessan Mac Giolla Mhuiris and published by . This book was released on 1986 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stability of Parallel Flows written by R. Betchov and published by Elsevier. This book was released on 2012-12-02 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stability of Parallel Flows provides information pertinent to hydrodynamical stability. This book explores the stability problems that occur in various fields, including electronics, mechanics, oceanography, administration, economics, as well as naval and aeronautical engineering. Organized into two parts encompassing 10 chapters, this book starts with an overview of the general equations of a two-dimensional incompressible flow. This text then explores the stability of a laminar boundary layer and presents the equation of the inviscid approximation. Other chapters present the general equations governing an incompressible three-dimensional flow, which requires the massive use of a computer. This book discusses as well the experimental studies on the oscillations of the boundary layer wherein the mean flow is affected by the presence of oscillations. The final chapter describes the concept of the stability of turbulent flows found in boundary layers, wakes, and jets. This book is a valuable resource for physicists, mathematicians, engineers, scientists, and researchers.
Download or read book OAR Quarterly Index of Current Research Results written by United States. Air Force. Office of Aerospace Research and published by . This book was released on 1959 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Angle of Attack Aerodynamics written by Josef Rom and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aerodynamics of aircraft at high angles of attack is a subject which is being pursued diligently, because the modern agile fighter aircraft and many of the current generation of missiles must perform well at very high incidence, near and beyond stall. However, a comprehensive presentation of the methods and results applicable to the studies of the complex aerodynamics at high angle of attack has not been covered in monographs or textbooks. This book is not the usual textbook in that it goes beyond just presenting the basic theoretical and experimental know-how, since it contains reference material to practical calculation methods and technical and experimental results which can be useful to the practicing aerospace engineers and scientists. It can certainly be used as a text and reference book for graduate courses on subjects related to high angles of attack aerodynamics and for topics related to three-dimensional separation in viscous flow courses. In addition, the book is addressed to the aerodynamicist interested in a comprehensive reference to methods of analysis and computations of high angle of attack flow phenomena and is written for the aerospace scientist and engineer who is familiar with the basic concepts of viscous and inviscid flows and with computational methods used in fluid dynamics.
Download or read book Transcendental Representations with Applications to Solids and Fluids written by Luis Manuel Braga da Costa Campos and published by CRC Press. This book was released on 2012-04-04 with total page 879 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building on the author's previous book in the series, Complex Analysis with Applications to Flows and Fields (CRC Press, 2010), Transcendental Representations with Applications to Solids and Fluids focuses on four infinite representations: series expansions, series of fractions for meromorphic functions, infinite products for functions with infinit
