Progress in Favre-Reynolds Stress Closures for Compressible Flows

Progress in Favre-Reynolds Stress Closures for Compressible Flows
Author: Virgil Adumitroaie
Publisher:
Total Pages: 48
Release: 1998
Genre:
ISBN:

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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.

Compressibility, Turbulence and High Speed Flow

Compressibility, Turbulence and High Speed Flow
Author: Thomas B. Gatski
Publisher: Academic Press
Total Pages: 343
Release: 2013-03-05
Genre: Science
ISBN: 012397318X

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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

Advanced Approaches in Turbulence

Advanced Approaches in Turbulence
Author: Paul Durbin
Publisher: Elsevier
Total Pages: 554
Release: 2021-07-24
Genre: Technology & Engineering
ISBN: 0128208902

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Advanced Approaches in Turbulence: Theory, Modeling, Simulation and Data Analysis for Turbulent Flows focuses on the updated theory, simulation and data analysis of turbulence dealing mainly with turbulence modeling instead of the physics of turbulence. Beginning with the basics of turbulence, the book discusses closure modeling, direct simulation, large eddy simulation and hybrid simulation. The book also covers the entire spectrum of turbulence models for both single-phase and multi-phase flows, as well as turbulence in compressible flow. Turbulence modeling is very extensive and continuously updated with new achievements and improvements of the models. Modern advances in computer speed offer the potential for elaborate numerical analysis of turbulent fluid flow while advances in instrumentation are creating large amounts of data. This book covers these topics in great detail. Covers the fundamentals of turbulence updated with recent developments Focuses on hybrid methods such as DES and wall-modeled LES Gives an updated treatment of numerical simulation and data analysis

Computational Fluid Dynamics

Computational Fluid Dynamics
Author: Jiri Blazek
Publisher: Elsevier
Total Pages: 491
Release: 2005-12-20
Genre: Science
ISBN: 0080529674

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Computational Fluid Dynamics (CFD) is an important design tool in engineering and also a substantial research tool in various physical sciences as well as in biology. The objective of this book is to provide university students with a solid foundation for understanding the numerical methods employed in today’s CFD and to familiarise them with modern CFD codes by hands-on experience. It is also intended for engineers and scientists starting to work in the field of CFD or for those who apply CFD codes. Due to the detailed index, the text can serve as a reference handbook too. Each chapter includes an extensive bibliography, which provides an excellent basis for further studies.

Development of a More General Reynolds Stress Closure for Swirling Flow

Development of a More General Reynolds Stress Closure for Swirling Flow
Author: S. B. Chin
Publisher:
Total Pages: 16
Release: 1988
Genre:
ISBN:

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This paper is concerned with the modelling of the return to isotropy part of the pressure strain term in homogeneous anisotropic turbulent flows. Analytical solutions of the transport equations of the invariants of the anisotropy tensor as well as that of turbulent kinetic energy as a function of the natural time of decay are provided and discussed. Principal components of the Reynolds stresses are obtained from the solution of a cubic equation which involves the invariants. It is shown that current models based on Rotta's hypothesis are subject to a constraint which is only satisfied by axisymmetric homogeneous turbulence, and the constraint can be eliminated by non-linear modelling. A physical picture of energy transfer among the Reynolds stress components which takes into account the influence of the third invariant on the process of return to isotropy is presented. Keywords: Second order closure; Reynolds stress model; Homogeneous turbulence; Non-linear effects; Swirling flows; Compressible flows.