EBookClubs

Read Books & Download eBooks Full Online

EBookClubs

Read Books & Download eBooks Full Online

Book Theoretical Experimental Investigation of Coherent Structure in the Turbulent Boundary Layer

Download or read book Theoretical Experimental Investigation of Coherent Structure in the Turbulent Boundary Layer written by C. R. Smith and published by . This book was released on 1982 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: This program combines both experimental flow visualization studies with analytical investigations of a series of phenomenological and theoretical models based upon three-dimensional, vortical flow structures developing and interacting in proximity to a solid surface. The experimental program considered a range of sub-problems including the effect of surface modifications on low-speed streak formation and drag, and the effect of vortex loop inter-action with a solid boundary. To augment visual studies, a computerized interface with the video system has been developed which allows quantitative data to be obtained from flow visualization pictures. The specific thrust of the theoretical studies has been focussed on three areas: (1) how two and three-dimensional vortex structures interact with wall boundary layers; (2) the development of a new type of prediction method for two-dimensional turbulent boundary-layer flows; and (3) improvement in numerical techniques for solving parabolic, boundary-layer equations.

Book Theoretical Experimental Investigation of Coherent Structure in the Turbulent Boundary Layer

Download or read book Theoretical Experimental Investigation of Coherent Structure in the Turbulent Boundary Layer written by D. E. Abbott and published by . This book was released on 1980 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project combines both experimental video flow visualization studies and theoretical investigations of a series of phenomenological and theoretical models based upon the three-dimensional details of convected, coherent structural elements of a turbulent flow as it interacts with a solid surface. The progress over the past year has led to the experimental consideration of range of sub-problems including high Reynolds Number (4,000,000) turbulent flows, the effect of surface modification on low-speed streak formation, and the effect of vortex loop interaction with a solid boundary. To augment the visualization pictures, a computerized video-digitizing system has been developed. Preliminary results show tremendous promise for obtaining quantitative data from flow visualization pictures. The specific thrust of the theoretical studies has been focussed on three areas: (1) how two- and three-dimensional vortex structures interact with wall boundary layers, (2) the development of a new type of prediction method for two-dimensional turbulent boundary-layer flows, and (3) improvement in numerical techniques for solving parabolic, boundary-layer equations. (Author).

Book Experimental Investigation of coherent structures in turbulent boundary layers

Download or read book Experimental Investigation of coherent structures in turbulent boundary layers written by Candace Elaine Wark and published by . This book was released on 1989 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Experimental Investigation of the Influence of the Turbulent Boundary Layer on the Pressure Distribution Over a Rigid Two dimensional Wavy Wall

Download or read book Experimental Investigation of the Influence of the Turbulent Boundary Layer on the Pressure Distribution Over a Rigid Two dimensional Wavy Wall written by Lado Muhlstein and published by . This book was released on 1971 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Scientific and Technical Aerospace Reports

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Investigation of Wall Bounded Turbulence Coherence and Chaos in a Model of Turbulent Boundary Layer

Download or read book Investigation of Wall Bounded Turbulence Coherence and Chaos in a Model of Turbulent Boundary Layer written by and published by . This book was released on 1991 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dynamics of coherent structures in the wall region of a turbulent channel flow is considered. The Karhunen-Loeve eigenfunctions and Galerkin procedure are used to derive the dynamical description. In a previous treatment of this problem by Aubry et al1 the analysis required an inhomogeneous pressure term to be supplied from outside the theory. In the first part of this paper this theory is reconsidered on the basis of the construction of wall eigenfunctions that have a full channel validity. As a result of the methods developed here, a well-posed Hermitian theory is developed and convergence questions do not arise. Among a number of important consequences is the fact that no exterior pressure is required by the present theory. In the second part of this paper it is shown that the behavior of the resulting model equa- tions include intermittency, quasiperiodic and chaotic solutions. In the final portion part of this paper three dimensional effects are introduced into the dynamics in order to produce a physically more realistic dynamical theory. It is felt that the bursting and ejection events in turbulent boundary-layers is given a more satisfactory explanation within this framework.

Book Experimental Investigation of the Turbulence Production Mechanism in Boundary Layers

Download or read book Experimental Investigation of the Turbulence Production Mechanism in Boundary Layers written by R. E. Falco and published by . This book was released on 1986 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past year we have discovered the mechanism of production of the long streaks and a mechanism for creation of vortex ring-like typical eddies, and have demonstrated the occurrence of both within a real turbulent boundary layer. These aspects were the missing links needed to complete the conceptual structural model. This model de-emphasizes the importance of hairpin vortices in wall layer transport. However, experimental determination of the relative importance of each of the elements of the model in low Reynolds number layers is far from complete, and we know very little of the Reynolds number dependence or pressure gradient dependence of the model. What we have learned so far suggests several critical parameters that can be manipulated to control the production of turbulence and hence reduce drag. In the proposed research we want to focus on acquiring additional data to support the rational theory that has been formed so as to provide the basis for determining how much leverage we have in our efforts to control boundary layer turbulence.

Book Workshop on Coherent Structure of Turbulent Boundary Layers

Download or read book Workshop on Coherent Structure of Turbulent Boundary Layers written by Charles Robert Smith and published by . This book was released on 1981 with total page 1116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book An Experimental Investigation of the Separation of a Turbulent Boundary Layer at M

Download or read book An Experimental Investigation of the Separation of a Turbulent Boundary Layer at M written by Irwin E. Vas and published by . This book was released on 1956 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Turbulent Boundary Layers Experiments Theory and Modelling

Download or read book Turbulent Boundary Layers Experiments Theory and Modelling written by ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (France) and published by . This book was released on 1980 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent experiments have demonstrated the persistence of coherent structures in turbulent shear flows and consequently have cast doubt on the usual local transport relations and even on the usefulness of Reynolds averaging, used in practically all modelling approaches. This symposium takes stock of the present situation in turbulence research and attempts to map out new directions in modelling and experimentation. It deals specifically with turbulent boundary layers, in both incompressible and compressible fluid flow. The existence coherent vortex structures has led to renewed interest in Lagrangean descriptions of the flow. Current work emphasizes flow-visualization methods together with development of sophisticated conditional sampling methods in hot-wire anemometry. Experimentalists have taken up the challenge presented by the existence of coherent structures, and new results are reported. Theoreticians interested in these new results face the difficult task of coming to grips with nonlinear vortex interactions. Development of a physically satisfactory and mathematically tractable theory is a formidable task. The decomposition of a fluctuating flow field into waves is a traditional, familiar approach while decomposition into horseshoe vortices (say) presents conceptual as well as mathematical difficulties. Computer modelling of turbulent shear flows using Reynolds averaged equations with various closure schemes is the most useful technique presently available. However, sooner or later, modelling will have to recognize the experimental fact of coherent structures.

Book Technical Abstract Bulletin

Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1980 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: