Generalized Wall Function for Complex Turbulent Flows

Generalized Wall Function for Complex Turbulent Flows PDF Author:
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 16

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Book Description

Generalized Wall Function for Complex Turbulent Flows

Generalized Wall Function for Complex Turbulent Flows PDF Author:
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 16

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Book Description


A Generalized Wall Function

A Generalized Wall Function PDF Author:
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 26

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Book Description


A Generalized Wall Function

A Generalized Wall Function PDF Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
ISBN: 9781724031136
Category : Science
Languages : en
Pages : 36

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Book Description
The asymptotic solutions, described by Tennekes and Lumley (1972), for surface flows in a channel, pipe or boundary layer at large Reynolds numbers are revisited. These solutions can be extended to more complex flows such as the flows with various pressure gradients, zero wall stress and rough surfaces, etc. In computational fluid dynamics (CFD), these solutions can be used as the boundary conditions to bridge the near-wall region of turbulent flows so that there is no need to have the fine grids near the wall unless the near-wall flow structures are required to resolve. These solutions are referred to as the wall functions. Furthermore, a generalized and unified law of the wall which is valid for whole surface layer (including viscous sublayer, buffer layer and inertial sublayer) is analytically constructed. The generalized law of the wall shows that the effect of both adverse and favorable pressure gradients on the surface flow is very significant. Such as unified wall function will be useful not only in deriving analytic expressions for surface flow properties but also bringing a great convenience for CFD methods to place accurate boundary conditions at any location away from the wall. The extended wall functions introduced in this paper can be used for complex flows with acceleration, deceleration, separation, recirculation and rough surfaces. Shih, Tsan-Hsing and Povinelli, Louis A. and Liu, Nan-Suey and Potapczuk, Mark G. and Lumley, J. L. Glenn Research Center NASA/TM-1999-209398, NAS 1.15:209398, E-11834, ICOMP-99-08

Engineering Turbulence Modelling and Experiments 5

Engineering Turbulence Modelling and Experiments 5 PDF Author: W. Rodi
Publisher: Elsevier
ISBN: 008053094X
Category : Mathematics
Languages : en
Pages : 1029

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Book Description
Turbulence is one of the key issues in tackling engineering flow problems. As powerful computers and accurate numerical methods are now available for solving the flow equations, and since engineering applications nearly always involve turbulence effects, the reliability of CFD analysis depends increasingly on the performance of the turbulence models. This series of symposia provides a forum for presenting and discussing new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. The papers in this set of proceedings were presented at the 5th International Symposium on Engineering Turbulence Modelling and Measurements in September 2002. They look at a variety of areas, including: Turbulence modelling; Direct and large-eddy simulations; Applications of turbulence models; Experimental studies; Transition; Turbulence control; Aerodynamic flow; Aero-acoustics; Turbomachinery flows; Heat transfer; Combustion systems; Two-phase flows. These papers are preceded by a section containing 6 invited papers covering various aspects of turbulence modelling and simulation as well as their practical application, combustion modelling and particle-image velocimetry.

Compressibility, Turbulence and High Speed Flow

Compressibility, Turbulence and High Speed Flow PDF Author: Thomas B. Gatski
Publisher: Academic Press
ISBN: 012397318X
Category : Science
Languages : en
Pages : 343

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Book Description
Compressibility, Turbulence and High Speed Flow introduces the reader to the field of compressible turbulence and compressible turbulent flows across a broad speed range, through a unique complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used. The book provides the reader with the necessary background and current trends in the theoretical and experimental aspects of compressible turbulent flows and compressible turbulence. Detailed derivations of the pertinent equations describing the motion of such turbulent flows is provided and an extensive discussion of the various approaches used in predicting both free shear and wall bounded flows is presented. Experimental measurement techniques common to the compressible flow regime are introduced with particular emphasis on the unique challenges presented by high speed flows. Both experimental and numerical simulation work is supplied throughout to provide the reader with an overall perspective of current trends. - An introduction to current techniques in compressible turbulent flow analysis - An approach that enables engineers to identify and solve complex compressible flow challenges - Prediction methodologies, including the Reynolds-averaged Navier Stokes (RANS) method, scale filtered methods and direct numerical simulation (DNS) - Current strategies focusing on compressible flow control

Turbulence: Numerical Analysis, Modelling and Simulation

Turbulence: Numerical Analysis, Modelling and Simulation PDF Author: William Layton
Publisher: MDPI
ISBN: 3038428094
Category : Mathematics
Languages : en
Pages : 229

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Book Description
This book is a printed edition of the Special Issue "Turbulence: Numerical Analysis, Modelling and Simulation" that was published in Fluids

Compressibility, Turbulence and High Speed Flow

Compressibility, Turbulence and High Speed Flow PDF Author: Thomas B. Gatski
Publisher: Elsevier
ISBN: 0080559123
Category : Science
Languages : en
Pages : 296

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Book Description
This book introduces the reader to the field of compressible turbulence and compressible turbulent flows across a broad speed range through a unique complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used. For the computation of turbulent compressible flows, current methods of averaging and filtering are presented so that the reader is exposed to a consistent development of applicable equation sets for both the mean or resolved fields as well as the transport equations for the turbulent stress field. For the measurement of turbulent compressible flows, current techniques ranging from hot-wire anemometry to PIV are evaluated and limitations assessed. Characterizing dynamic features of free shear flows, including jets, mixing layers and wakes, and wall-bounded flows, including shock-turbulence and shock boundary-layer interactions, obtained from computations, experiments and simulations are discussed. - Describes prediction methodologies including the Reynolds-averaged Navier Stokes (RANS) method, scale filtered methods and direct numerical simulation (DNS) - Presents current measurement and data analysis techniques - Discusses the linkage between experimental and computational results necessary for validation of numerical predictions - Meshes the varied results of computational and experimental studies in both free and wall-bounded flows to provide an overall current view of the field

New Results in Numerical and Experimental Fluid Mechanics VII

New Results in Numerical and Experimental Fluid Mechanics VII PDF Author: Andreas Dillmann
Publisher: Springer Science & Business Media
ISBN: 3642142435
Category : Technology & Engineering
Languages : en
Pages : 629

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Book Description
th This volume contains the papers presented at the 16 DGLR/STAB-Symposium held at the Eurogress Aachen and organized by RWTH Aachen University, Germany, November, 3 - 4, 2008. STAB is the German Aerospace Aerodynamics Association, founded towards the end of the 1970's, whereas DGLR is the German Society for Aeronautics and Astronautics (Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal Oberth e.V.). The mission of STAB is to foster development and acceptance of the discipline “Aerodynamics” in Germany. One of its general guidelines is to concentrate resources and know-how in the involved institutions and to avoid duplication in research work as much as possible. Nowadays, this is more necessary than ever. The experience made in the past makes it easier now, to obtain new knowledge for solving today's and tomorrow's problems. STAB unites German scientists and engineers from universities, research-establishments and industry doing research and project work in numerical and experimental fluid mechanics and aerodynamics for aerospace and other applications. This has always been the basis of numerous common research activities sponsored by different funding agencies. Since 1986 the symposium has taken place at different locations in Germany every two years. In between STAB workshops regularly take place at the DLR in Göttingen.

Turbulence Models and Their Application

Turbulence Models and Their Application PDF Author: Tuncer Cebeci
Publisher: Springer Science & Business Media
ISBN: 9783540402886
Category : Science
Languages : en
Pages : 140

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Book Description
After a brief review of the more popular turbulence models, the author presents and discusses accurate and efficient numerical methods for solving the boundary-layer equations with turbulence models based on algebraic formulas (mixing length, eddy viscosity) or partial-differential transport equations. A computer program employing the Cebeci-Smith model and the k-e model for obtaining the solution of two-dimensional incompressible turbulent flows without separation is discussed in detail and is presented in the accompanying CD.

Modeling Complex Turbulent Flows

Modeling Complex Turbulent Flows PDF Author: Manuel D. Salas
Publisher: Springer Science & Business Media
ISBN: 9401147248
Category : Science
Languages : en
Pages : 385

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Book Description
Turbulence modeling both addresses a fundamental problem in physics, 'the last great unsolved problem of classical physics,' and has far-reaching importance in the solution of difficult practical problems from aeronautical engineering to dynamic meteorology. However, the growth of supercom puter facilities has recently caused an apparent shift in the focus of tur bulence research from modeling to direct numerical simulation (DNS) and large eddy simulation (LES). This shift in emphasis comes at a time when claims are being made in the world around us that scientific analysis itself will shortly be transformed or replaced by a more powerful 'paradigm' based on massive computations and sophisticated visualization. Although this viewpoint has not lacked ar ticulate and influential advocates, these claims can at best only be judged premature. After all, as one computational researcher lamented, 'the com puter only does what I tell it to do, and not what I want it to do. ' In turbulence research, the initial speculation that computational meth ods would replace not only model-based computations but even experimen tal measurements, have not come close to fulfillment. It is becoming clear that computational methods and model development are equal partners in turbulence research: DNS and LES remain valuable tools for suggesting and validating models, while turbulence models continue to be the preferred tool for practical computations. We believed that a symposium which would reaffirm the practical and scientific importance of turbulence modeling was both necessary and timely.