Author: Ridha AbidPublisher:
ISBN:
Category :
Languages : en
Pages : 36
Book Description
On Prediction of Equilibrium States in Homogeneous Compressible Turbulence
Author: Ridha AbidOn Prediction of Equilibrium States in Homogeneous Compressible Turbulence
Author: National Aeronautics and Space Adm NasaPublisher: Independently Published
ISBN: 9781728848952
Category : Science
Languages : en
Pages : 38
Book Description
Direct numerical simulations of compressible, homogeneous, turbulent shear flows are used to evaluate Reynolds stress models. Three pressure-strain models, which are either linear, quadratic, or cubic in the anisotropy tensor are considered. Dilatational dissipation and pressure-strain correlation models do not correctly capture the compressibility effects seen in the direct simulations. In particular, the increase in the anisotropy of normal stresses and the reduction in the shear stress are not reproduced by any of the models. Also, the use of the incompressible form of the dissipation-rate equation to determine the solenoidal part of the dissipation is found to be questionable. Abid, Ridha Unspecified Center NAS1-19299; RTOP 505-70-62-15
Scientific and Technical Aerospace Reports
Author: Theoretical, Experimental, and Numerical Contributions to the Mechanics of Fluids and Solids
Author: James CaseyPublisher: Birkhäuser
ISBN: 3034892292
Category : Technology & Engineering
Languages : en
Pages : 850
Book Description
This special issue of ZAMP is published to honor Paul M. Naghdi for his contributions to mechanics over the last forty years and more. It is offered in celebration of his long, productive career in continuum mechan ics; a career which has been marked by a passion for the intrinsic beauty of the subject, an uncompromising adherence to academic standards, and an untiring devotion to our profession. Originally, this issue was planned in celebration of Naghdi's 70th birthday, which occurred on 29 March 1994. But, as the papers were being prepared for the press, it became evident that the illness from which Professor Naghdi had been suffering during recent months was extremely serious. On 26 May 1994, a reception took place in the Department of Mechanical Engineering at Berkeley, at which Naghdi received The Berkeley Citation (which is given in lieu of an honorary degree) and where he was also presented with the Table of Contents of the present collection. Subse quently, he had the opportunity to read the papers in manuscript form. He was very touched that his colleagues had chosen to honor him with their fine contributions. The knowledge that he was held in such high esteem by his fellow scientists brought a special pleasure and consolation to him in his last weeks. On Saturday evening, 9 July 1994, Paul Naghdi succumbed to the lung cancer which he had so courageously endured.
Modeling Complex Turbulent Flows
Author: Manuel D. SalasPublisher: Springer Science & Business Media
ISBN: 9780792355908
Category : Science
Languages : en
Pages : 402
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.
Compressibility, Turbulence and High Speed Flow
Author: Thomas B. GatskiPublisher: Academic Press
ISBN: 012397318X
Category : Science
Languages : en
Pages : 343
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
Transition, Turbulence and Combustion
Author: M.Y. HussainiPublisher: Springer Science & Business Media
ISBN: 9401110328
Category : Science
Languages : en
Pages : 394
Book Description
These two volumes contain the proceedings of the Workshop on Transition, Turbulence and Combustion, sponsored by the Insti tute for Computer Applications in Science and Engineering (ICASE) and the NASA Langley Research Center (LaRC), during June 7 to July 2, 1993. Volume I contains the contributions from the transi tion research, and Volume II contains the contributions from both the turbulence and combustion research. This is the third workshop in the series on the subject. The first was held in 1989, the second in 1991, and their proceedings were published by Springer-Verlag under the titles "Instability and Transition" (edited by M. Y. Hussaini and R. G. Voigt) and "Instability, Transition and Turbulence" (edited by M. Y. Hussaini, A. Kumar and C. L. Streett) respectively. The objectives of these workshops are to expose the academic community to current technologically important issues of transition, turbulence and combustion, and to acquaint the academic commu nity with the unique combination of theoretical, computational and experimental capabilities at LaRC. It is hoped these will foster con tinued interactions, and accelerate progress in elucidating the funda mental phenomena of transition, turbulence and combustion. The research areas of interest in transition covered the full range of the subject: linear and nonlinear stability, direct and large-eddy simulation and phenomenological modeling of the transition zone.
Homogeneous Turbulence Dynamics
Author: Pierre SagautPublisher: Springer
ISBN: 3319731629
Category : Science
Languages : en
Pages : 912
Book Description
This book provides state-of-the-art results and theories in homogeneous turbulence, including anisotropy and compressibility effects with extension to quantum turbulence, magneto-hydodynamic turbulence and turbulence in non-newtonian fluids. Each chapter is devoted to a given type of interaction (strain, rotation, shear, etc.), and presents and compares experimental data, numerical results, analysis of the Reynolds stress budget equations and advanced multipoint spectral theories. The role of both linear and non-linear mechanisms is emphasized. The link between the statistical properties and the dynamics of coherent structures is also addressed. Despite its restriction to homogeneous turbulence, the book is of interest to all people working in turbulence, since the basic physical mechanisms which are present in all turbulent flows are explained. The reader will find a unified presentation of the results and a clear presentation of existing controversies. Special attention is given to bridge the results obtained in different research communities. Mathematical tools and advanced physical models are detailed in dedicated chapters.
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