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Compressibility Corrections To Closure Approximations For Turbulent Flow Simulations
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Book Synopsis Compressibility Corrections to Closure Approximations for Turbulent Flow Simulations by :
Download or read book Compressibility Corrections to Closure Approximations for Turbulent Flow Simulations written by and published by . This book was released on 2003 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: We summarize some modifications to the usual closure approximations for statistical models of turbulence that are necessary for use with compressible fluids at all Mach numbers. We concentrate here on the gradient-flu approximation for the turbulent heat flux, on the buoyancy production of turbulence kinetic energy, and on a modification of the Smagorinsky model to include buoyancy. In all cases, there are pressure gradient terms that do not appear in the incompressible models and are usually omitted in compressible-flow models. Omission of these terms allows unphysical rates of entropy change.
Book Synopsis Turbulence Compressibility Corrections by :
Download or read book Turbulence Compressibility Corrections written by and published by . This book was released on 1994 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Toward Understanding and Modeling Compressibility Effects on Velocity Gradients in Turbulence by : Sawan Suman
Download or read book Toward Understanding and Modeling Compressibility Effects on Velocity Gradients in Turbulence written by Sawan Suman and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Development of improved turbulence closure models for compressible fluid flow simulations requires better understanding of the effects of compressibility on various underlying processes of turbulence. Fundamental studies of turbulent velocity gradients hold the key to understanding several non-linear processes like material element deformation, energy cascading, intermittency and mixing. Experiments, direct numerical simulation (DNS) and simple mathematical models are three approaches to study velocity gradients. With the goal of furthering our understanding of the effects of compressibility on turbulent velocity gradients, this dissertation (i) employs DNS results to characterize some of the effects of compressibility on turbulent velocity gradients, and (ii) develops simple mathematical models for velocity gradient dynamics in compressible turbulence. In the first part of the dissertation, effects of compressibility on velocity gradient invariants and the local topology of compressible turbulence are characterized employing DNS results of compressible decaying isotropic turbulence. Joint statistics of second and third invariants of velocity gradient tensor and the exact probability of occurrence of associated topologies conditioned upon dilatation (degree of compression/expansion of fluid) are computed. These statistics are found to be (i) highly dependent on dilatation and (ii) substantially different from the statistics observed in incompressible turbulence. These dilatation-conditioned statistics of compressible turbulence, however, are found to be fairly independent of Mach number and Reynolds number. In the second part of the dissertation, two mathematical models for compressible velocity gradient dynamics are developed. To take into account the significant aero-thermodynamic coupling that exists in compressible flows, the models are derived explicitly using the continuity, energy and state equations, along with the momentum equation. The modeling challenge involved in the development of these models lies in capturing the inherently non-local nature of pressure and viscous effects as a function of local terms to derive a closed set of ordinary differential equations. The models developed in this dissertation are evaluated in a variety of flow regimes - incompressible limit (low Mach number); pressure-released limit (extremely high Mach number); and intermediate (sub-sonic Mach numbers) - and are shown to recover a range of known compressibility effects.
Book Synopsis Progress in Turbulence Modeling for Complex Flow Fields Including Effects of Compressibility by : David C. Wilcox
Download or read book Progress in Turbulence Modeling for Complex Flow Fields Including Effects of Compressibility written by David C. Wilcox and published by . This book was released on 1980 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Compressibility, Turbulence and High Speed Flow by : Thomas B. Gatski
Download or read book Compressibility, Turbulence and High Speed Flow written by Thomas B. Gatski and published by Elsevier. This book was released on 2009-07-18 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used." --Book Jacket.
Book Synopsis A Compressible Navier-Stokes Solver with Two-equation and Reynolds Stress Turbulence Closure Models by : Joseph H. Morrison
Download or read book A Compressible Navier-Stokes Solver with Two-equation and Reynolds Stress Turbulence Closure Models written by Joseph H. Morrison and published by . This book was released on 1992 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781722918859 Total Pages :40 pages Book Rating :4.9/5 (188 download)
Book Synopsis Turbulence Compressibility Corrections by : National Aeronautics and Space Administration (NASA)
Download or read book Turbulence Compressibility Corrections written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-15 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The basic objective of this research was to identify, develop and recommend turbulence models which could be incorporated into CFD codes used in the design of the National AeroSpace Plane vehicles. To accomplish this goal, a combined effort consisting of experimental and theoretical phases was undertaken. The experimental phase consisted of a literature survey to collect and assess a database of well documented experimental flows, with emphasis on high speed or hypersonic flows, which could be used to validate turbulence models. Since it was anticipated that this database would be incomplete and would need supplementing, additional experiments in the NASA Ames 3.5-Foot Hypersonic Wind Tunnel (HWT) were also undertaken. The theoretical phase consisted of identifying promising turbulence models through applications to simple flows, and then investigating more promising models in applications to complex flows. The complex flows were selected from the database developed in the first phase of the study. For these flows it was anticipated that model performance would not be entirely satisfactory, so that model improvements or corrections would be required. The primary goals of the investigation were essentially achieved. A large database of flows was collected and assessed, a number of additional hypersonic experiments were conducted in the Ames HWT, and two turbulence models (kappa-epsilon and kappa-omega models with corrections) were determined which gave superior performance for most of the flows studied and are now recommended for NASP applications. Coakley, T. J. and Horstman, C. C. and Marvin, J. G. and Viegas, J. R. and Bardina, J. E. and Huang, P. G. and Kussoy, M. I. Ames Research Center RTOP 505-70-59...
Book Synopsis Engineering Turbulence Modelling and Experiments - 4 by : D. Laurence
Download or read book Engineering Turbulence Modelling and Experiments - 4 written by D. Laurence and published by Elsevier. This book was released on 1999-04-14 with total page 975 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings contain the papers presented at the 4th International Symposium on Engineering Turbulence Modelling and Measurements held at Ajaccio, Corsica, France from 24-26 May 1999. It follows three previous conferences on the topic of engineering turbulence modelling and measurements. The purpose of this series of symposia is to provide a forum for presenting and discussing new developments in the area of turbulence modelling and measurements, with particular emphasis on engineering-related problems. Turbulence is still 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 more and more on the performance of the turbulence models. Successful simulation of turbulence requires the understanding of the complex physical phenomena involved and suitable models for describing the turbulent momentum, heat and mass transfer. For the understanding of turbulence phenomena, experiments are indispensable, but they are equally important for providing data for the development and testing of turbulence models and hence for CFD software validation.
Book Synopsis Some Results Relevant to Statistical Closures for Compressible Turbulence by : J. R. Ristorcelli
Download or read book Some Results Relevant to Statistical Closures for Compressible Turbulence written by J. R. Ristorcelli and published by . This book was released on 1998 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Progress in Favre-Reynolds Stress Closures for Compressible Flows by : Virgil Adumitroaie
Download or read book Progress in Favre-Reynolds Stress Closures for Compressible Flows written by Virgil Adumitroaie and published by . This book was released on 1998 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: A closure for the compressible portion of the pressure strain covariance is developed. It is shown that, within the context of a pressure strain closure assumption linear in the Reynolds stresses, an expression for the pressure dilatation can be used to construct a representation for the pressure strain. Additional closures for the unclosed terms in the Favre Reynolds stress equations involving the mean acceleration are also constructed. The closures accommodate compressibility corrections depending on the magnitude of the turbulent Mach number, the mean density gradient, the mean pressure gradient, the mean dilatation, and, of course, the mean velocity gradients. The effects of the compressibility corrections are consistent with current DNS results. Using the compressible pressure strain and mean acceleration closures in the Favre Reynolds stress equations an algebraic closure for the Favre Reynolds stresses is constructed. Noteworthy is the fact that, in the absence of mean velocity gradients, the mean density gradient produces Favre Reynolds stresses in accelerating mean flows. Computations of the mixing layer using the compressible closures developed are described. Favre Reynolds stress closure and two equation algebraic models are compared to laboratory data. The mixing layer configuration computations are compared to laboratory data; since the laboratory data for the turbulence stresses is inconsistent, this comparison is inconclusive. Comparisons for the spread rate reduction indicate a sizable decrease in the mixing layer growth rate.
Book Synopsis A Compressible Navier-Stokes Solver with Two-equation and Reynolds Stress Turbulence Close Models by : Joseph Hicks Morrison
Download or read book A Compressible Navier-Stokes Solver with Two-equation and Reynolds Stress Turbulence Close Models written by Joseph Hicks Morrison and published by . This book was released on 1992 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
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 Synopsis Advances in Turbulence IV by : F.T. Nieuwstadt
Download or read book Advances in Turbulence IV written by F.T. Nieuwstadt and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: The European Turbulence Conferences have been organized under the auspices of the European Mechanics Committee (Euromech) to provide a forum for discussion and exchange of recent and new results in the field of turbulence. The first conference was organized in Lyon in 1986 with 152 participants. The second and third conferences were held in Berlin (1988) and Stockholm (1990) with 165 and 172 participants respectively. The fourth was organized in Delft from 30 June to 3 July 1992 by the J.M. Burgers Centre. There were 214 participants from 22 countries. This steadily growing number of participants demonstrates both the success and need for this type of conference. The main topics of the Fourth European Turbulence Conference were: Dynamical Systems and Transition; Statistical Physics and Turbulence; Experiments and Novel Experimental Techniques; Particles and Bubbles in Turbulence; Simulation Methods; Coherent Structures; Turbulence Modelling and Compressibility Effects. In addition a special session was held on the subject of CeBular Automata. Each of the sessions was introduced with a survey lecture. The lecturers were: W. Eckhaus, AJ. Libchaber, L. Katgerman, F. Durst, M. Lesieur, B. Legras, D.G. Dritschel and P. Bradshaw. The contributions of the participants were subdivided into oral and poster presentations. In addition to the normal program, some Speciai Interest Groups of Ercoftac (European Research Community on Flow, Turbulence and Combustion) presented their research activities in the form of a poster.
Book Synopsis New Results in Numerical and Experimental Fluid Mechanics III by : Siegfried Wagner
Download or read book New Results in Numerical and Experimental Fluid Mechanics III written by Siegfried Wagner and published by Springer Science & Business Media. This book was released on 2002-02-26 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the papers of a German symposium dealing with research and project work in numerical and experimental aerodynamics and fluidmechanics for aerospace and other applications. It gives a broad overview over the ongoing work in this field in Germany.
Book Synopsis Assessment of Closure Coefficients for Compressible-flow Turbulence Models by :
Download or read book Assessment of Closure Coefficients for Compressible-flow Turbulence Models written by and published by . This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Progress in Computational Flow-Structure Interaction by : Werner Haase
Download or read book Progress in Computational Flow-Structure Interaction written by Werner Haase and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aircraft design processes require extensive work in the area of both aerodynamics and structure, fonning an environment for aeroelasticity investigations. Present and future designs of European aircraft are characterized by an ever increasing aircraft size and perfonnance. Strong weight saving requirements are met by introduction of new materials, leading to more flexible structure of the aircraft. Consequently, aeroelastic phenomena such as vortex-induced aeroelastic oscillations and moving shock waves can be predominant and may have a significant effect on the aircraft perfonnance. Hence, the ability to estimate reliable margins for aeroelastic instabilities (flutter) or dynamic loads (buffeting) is a major concern to the aircraft designer. As modern aircrafts have wing bending modes with frequencies that are low enough to influence the flight control system, demands on unsteady aerodynamics and structural analysis to predict flight control effectiveness and riding comfort for passengers are extremely high. Therefore, the aircraft industries need an improved capacity of robust, accurate and reliable prediction methods in the coupled aeroelastic, flight mechanics and loads disciplines. In particular, it is necessary to develop/improve and calibrate the numerical tools in order to predict with high level of accuracy and capability complex and non-classical aeroelastic phenomena, including aerodynamic non-linearities, such as shock waves and separation, as well as structural non-linearities, e. g. control surface free-play. Nowadays, robust methods for structural analysis and linearised unsteady aerodynamics are coupled and used by the aircraft industry to computationally clear a new design from flutter.
Book Synopsis Some Results Relevant to Statistical Closures for Compressible Turbulence by : Joseph Raymond Ristorcelli
Download or read book Some Results Relevant to Statistical Closures for Compressible Turbulence written by Joseph Raymond Ristorcelli and published by . This book was released on 1998 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
