Download or read book Boundary layer induced Vortex Instability written by Masood Parang and published by . This book was released on 1972 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Liutex and Its Applications in Turbulence Research written by Chaoqun Liu and published by Academic Press. This book was released on 2020-10-29 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liutex and Its Applications in Turbulence Research reviews the history of vortex definition, provides an accurate mathematical definition of vortices, and explains their applications in flow transition, turbulent flow, flow control, and turbulent flow experiments. The book explains the term "Rortex" as a mathematically defined rigid rotation of fluids or vortex, which could help solve many longstanding problems in turbulence research. The accurate mathematical definition of the vortex is important in a range of industrial contexts, including aerospace, turbine machinery, combustion, and electronic cooling systems, so there are many areas of research that can benefit from the innovations described here. This book provides a thorough survey of the latest research in generalized and flow-thermal, unified, law-of-the-wall for wall-bounded turbulence. Important theory and methodologies used for developing these laws are described in detail, including: the classification of the conventional turbulent boundary layer concept based on proper velocity scaling; the methodology for identification of the scales of velocity, temperature, and length needed to establish the law; and the discovery, proof, and strict validations of the laws, with both Reynolds and Prandtl number independency properties using DNS data. The establishment of these statistical laws is important to modern fluid mechanics and heat transfer research, and greatly expands our understanding of wall-bounded turbulence. Provides an accurate mathematical definition of vortices Provides a thorough survey of the latest research in generalized and flow-thermal, unified, law-of-the-wall for wall-bounded turbulence Explains the term “Rortex as a mathematically defined rigid rotation of fluids or vortex Covers the statistical laws important to modern fluid mechanics and heat transfer research, and greatly expands our understanding of wall-bounded turbulence
Download or read book Three dimensional Laminar Boundary layer Analysis of Upwash Patterns and Entrained Vortex Formation on Sharp Cones at Angle of Attack written by John C. Adams (Jr.) and published by . This book was released on 1971 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: Application of three-dimensional inviscid and viscous (laminar boundary layer) analyses for cold wall hypersonic flows over sharp cones at incidence is presented relative to experimental data, showing surface upwash angles and entrained vortex formation leading to crossflow-induced boundary-layer transition. Three-dimensional neutral inviscid stability theory for stationary disturbances is used to calculate the angular orientation of the entrained vortices in the boundary layer while a maximum crossflow Reynolds number concept is applied for correlation of the onset to vortex formation due to crossflow instability.
Download or read book Boundary Layer Instability Induced by Distributed Surface Suction microform written by Philip James Douglas Roberts and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2001 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: The linear instability of accelerated, decelerated and flat plate boundary layers modified by uniform surface suction blowing and/or periodic (distributed) wall suction is investigated. All boundary layer flows considered in this work are assumed to be incompressible and parallel. Small but finite suction non-uniformities are found to induce an instability in the form of stationary streamwise vortices for each of the boundary layer configurations studied; this instability is shown to be (i) strongly influenced by the suction non-uniformity amplitude and flow Reynolds number but only (ii) moderately influenced by the application of uniform suction or uniform blowing. It is found that the classical TS (Tollmien-Schlichting) wave instability changes in a complex manner when the suction non-uniformity amplitude is varied. Oblique TS waves are shown in several instances to be more unstable than two-dimensional TS waves depending on the suction non-uniformity magnitude and the type of boundary layer under consideration. A resonance mechanism that causes a strong flow response is demonstrated to occur when infinitesimally small surface suction non-uniformities travel with the phase speed and wave number nearby either the neutral or most weakly attenuated Tollmien-Schlichting waves.
Download or read book The Goertler Vortex Instability Mechanism in Three dimensional Boundary Layers written by Institute for Computer Applications in Science and Engineering and published by . This book was released on 1984 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The G rtler Vortex Instability Mechanism in Three dimensional Boundary Layers written by Philip Hall and published by . This book was released on 1984 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vortex Induced Boundary Layer Separation written by Vallorie Jeanne Peridier and published by . This book was released on 1989 with total page 642 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unsteady boundary-layer separation at high Reynolds numbers, Re, is considered on a theoretical and computational basis. Whenever an external inviscid flow induces a region of adverse pressure gradient near a wall, the development of recirculating eddies in the boundary layer is common. An unsteady viscous-inviscid interaction often follows in the form of a local boundary-layer eruption and abrupt ejection of near-wall vorticity into the external flow. The dynamics of this process, as it develops in an initially thin boundary layer, is considered. As interaction ensues, the flow focuses into a band which progressively narrows in the streamwise direction. The complex flow development is extremely difficult to resolve using conventional Eulerian methods; here the boundary-layer solutions are obtained using Lagrangian methods, wherein trajectories of a large number of fluid particles are computed. The algorithms developed are general but are applied here to the problem of the boundary-layer induced by a two-dimensional vortex above an infinite plane wall. Solutions are obtained for the limit problem Re approaches limit of infinity, and for Re large but finite using an interacting boundary-layer approach. The present results describe the initial stages of a strong unsteady viscous-inviscid interaction; apparently it is necessary to account for the effect of normal pressure variations to continue the interaction. Keywords: Vortices; Turbulent boundary layer; Turbulent bursts; Boundary-layer eruptions; Unsteady interactions; Boundary layer flow separation. (edc).
Download or read book Vortex Instabilities in 3D Boundary Layers The Relationship Between Goertler and Crossflow Vortices written by Institute for Computer Applications in Science and Engineering and published by . This book was released on 1990 with total page 82 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Instability Transition and Turbulence written by M. Yousuff Hussaini and published by . This book was released on 1992 with total page 658 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 Inviscid Vortex Motions in Weakly Three dimensional Boundary Layers and Their Relation with Instabilities in Stratified Shear Flows written by Institute for Computer Applications in Science and Engineering and published by . This book was released on 1992 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Inviscid Secondary Instability of Fully Nonlinear Longitudinal Vortex Structures in Growing Boundary Layers written by Institute for Computer Applications in Science and Engineering and published by . This book was released on 1990 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Study of Vortex Arrays Induced Artificially and from Centrifugal Instabilities written by Michael F. Tuzzolo and published by . This book was released on 1989 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Boundary Layer and Flow Control written by G. V. Lachmann and published by Elsevier. This book was released on 2014-05-12 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boundary Layer and Flow Control: Its Principles and Application, Volume 2 focuses on the layer of fluid in the immediate area of a bounding surface where the effects of viscosity are substantial. This book is organized into two main topics—boundary layer control for low drag, and shock-induced separation and its prevention by design and boundary layer control. It specifically discusses the nature of transition, effect of two-dimensional and isolated roughness on laminar flow, and progress in the design of low drag aerofoils. The onset of separation effects for aerofoils and wings, shock-induced separation for laminar boundary layers, and shock-induced separation for laminar boundary layers are also deliberated. This volume is recommended to physicists and specialists interested in boundary layer and flow control.
Download or read book Streamwise Vortex Instability and Hypersonic Boundary Layer Transition on the Hyper 2000 written by and published by . This book was released on 2003 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the closely coupled nature of hypersonic airbreathing vehicles, the boundary layer transition mechanisms on the forebody ahead of the scramjet inlet are not well understood. Transition induced by the growth of streamwise vortices is studied on a scramjet forebody geometry similar to the Hyper-X. Flow visualization methods are developed in Purdue's Boeing/AFOSR Mach-6 Quiet Tunnel. Fluorescent oil-flow visualization is used to complement instability measurements obtained with temperature-sensitive-paints. The separation zone near the first compression corner is visualized with oil-flow experiments. These experiments also reveal the presence of regularly spaced streamwise vortices on the compression ramp even in the absence of controlled disturbance generators. The growth and decay of these vortices are inferred from heat-transfer measurements using temperature-sensitive paints. Repeatable vortices are generated by wrapping tapes around the leading edge.
Download or read book Vortex Methods Selected Papers Of The First International Conference On Vortex Methods written by Kyoji Kamemoto and published by World Scientific. This book was released on 2000-05-11 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vortex methods have been developed and applied to many kinds of flows related to various problems in wide engineering and scientific fields. The purpose of the First International conference on Vortex methods was to provide an opportunity for engineers and scientists to present their achievements, exchange ideas and discuss new developments in mathematical and physical modeling techniques and engineering applications of vortex methods.
Download or read book Vortex Instability of Heated Boundary Layers written by Pervez Iqbal and published by . This book was released on 1991 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
