Large-Eddy Simulations of Turbulence

Large-Eddy Simulations of Turbulence PDF Author: M. Lesieur
Publisher: Cambridge University Press
ISBN: 9780521781244
Category : Mathematics
Languages : en
Pages : 240

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Book Description
Large-Eddy Simulations of Turbulence is a reference for LES, direct numerical simulation and Reynolds-averaged Navier-Stokes simulation.

Large-Eddy Simulations of Turbulence

Large-Eddy Simulations of Turbulence PDF Author: M. Lesieur
Publisher: Cambridge University Press
ISBN: 9780521781244
Category : Mathematics
Languages : en
Pages : 240

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Book Description
Large-Eddy Simulations of Turbulence is a reference for LES, direct numerical simulation and Reynolds-averaged Navier-Stokes simulation.

Optimal Large Eddy Simulation of Turbulence

Optimal Large Eddy Simulation of Turbulence PDF Author: Robert deLancey Moser
Publisher:
ISBN:
Category : Navier-Stokes equations
Languages : en
Pages : 184

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Book Description


Optimal Large Eddy Simulation of Turbulence

Optimal Large Eddy Simulation of Turbulence PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Optimal LES modeling is a new approach to the development of subgrid models of turbulence. It has been found to produce accurate LES simulations when based on reliable statistical information. Now, the primary effort in optimal model development is the determination of this statistical information from theoretical considerations, with minimal empirical input. The validity of the theoretically determined statistics is being tested against experimental and DNS data. When small-scales are isotropic, Kolmogorov theory, the quasi-normal approximation and a dynamic procedure allow optimal models to be constructed with no empirical input. Such models have been found to perform well, though the dynamic procedure has not yet been tested in this context. Tests using channel flow DNS show that, except for a region very near the wall, the quasi-normal approximation is valid. Further, for the log-region, a representation for the anisotropy and inhomogeneity of the statistics is being developed. Thus, the above modeling approach can be adapted to near-wall turbulence, except for the thin viscous region. To handle this wall layer, a filtered boundary optimal LES model is being developed and tested.

Modeling Turbulence Using Optimal Large Eddy Simulation

Modeling Turbulence Using Optimal Large Eddy Simulation PDF Author: Henry Chang
Publisher:
ISBN:
Category :
Languages : en
Pages : 272

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Book Description
Most flows in nature and engineering are turbulent, and many are wall-bounded. Further, in turbulent flows, the turbulence generally has a large impact on the behavior of the flow. It is therefore important to be able to predict the effects of turbulence in such flows. The Navier-Stokes equations are known to be an excellent model of the turbulence phenomenon. In simple geometries and low Reynolds numbers, very accurate numerical solutions of the Navier-Stokes equations (direct numerical simulation, or DNS) have been used to study the details of turbulent flows. However, DNS of high Reynolds number turbulent flows in complex geometries is impractical because of the escalation of computational cost with Reynolds number, due to the increasing range of spatial and temporal scales. In Large Eddy Simulation (LES), only the large-scale turbulence is simulated, while the effects of the small scales are modeled (subgrid models). LES therefore reduces computational expense, allowing flows of higher Reynolds number and more complexity to be simulated. However, this is at the cost of the subgrid modeling problem. The goal of the current research is then to develop new subgrid models consistent with the statistical properties of turbulence. The modeling approach pursued here is that of "Optimal LES". Optimal LES is a framework for constructing models with minimum error relative to an ideal LES model. The multi-point statistics used as input to the optimal LES procedure can be gathered from DNS of the same flow. However, for an optimal LES to be truly predictive, we must free ourselves from dependence on existing DNS data. We have done this by obtaining the required statistics from theoretical models which we have developed. We derived a theoretical model for the three-point third-order velocity correlation for homogeneous, isotropic turbulence in the inertial range. This model is shown be a good representation of DNS data, and it is used to construct optimal quadratic subgrid models for LES of forced isotropic turbulence with results which agree well with theory and DNS. The model can also be filtered to determine the filtered two-point third-order correlation, which describes energy transfer among filtered (large) scales in LES. LES of wall-bounded flows with unresolved wall layers commonly exhibit good prediction of mean velocities and significant over-prediction of streamwise component energies in the near-wall region. We developed improved models for the nonlinear term in the filtered Navier-Stokes equation which result in better predicted streamwise component energies. These models involve (1) Reynolds decomposition of the nonlinear term and (2) evaluation of the pressure term, which removes the divergent part of the nonlinear models. These considerations significantly improved the performance of our optimal models, and we expect them to apply to other subgrid models as well.

Optimal Large-eddy Simulation of Turbulent Channel Flow

Optimal Large-eddy Simulation of Turbulent Channel Flow PDF Author: Stefan Völker
Publisher:
ISBN:
Category :
Languages : en
Pages : 224

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Turbulent Shear Flows 8

Turbulent Shear Flows 8 PDF Author: Franz Durst
Publisher: Springer Science & Business Media
ISBN: 3642776744
Category : Science
Languages : en
Pages : 419

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Book Description
This volume contains a selection of the papers presented at the Eighth Symposium on Turbulent Shear Flows held at the Technical University of Munich, 9-11 September 1991. The first of these biennial international symposia was held at the Pennsylvania State Uni versity, USA, in 1977; subsequent symposia have been held at Imperial College, London, England; the University of California, Davis, USA; the University of Karlsruhe, Ger many; Cornell University, Ithaca, USA; the Paul Sabatier University, Toulouse, France; and Stanford University, California, USA. The purpose of this series of symposia is to provide a forum for the presentation and discussion of new developments in the field of turbulence, especially as related to shear flows of importance in engineering and geo physics. From the 330 extended abstracts submitted for this symposium, 145 papers were presented orally and 60 as posters. Out of these, we have selected twenty-four papers for inclusion in this volume, each of which has been revised and extended in accordance with the editors' recommendations. The following four theme areas were selected after consideration of the quality of the contributions, the importance of the area, and the selection made in earlier volumes: - wall flows, - separated flows, - compressibility effects, - buoyancy, rotation, and curvature effects. As in the past, each section corresponding to the above areas begins with an introduction by an authority in the field that places the individual contributions in context with one another and with related research.

Large Eddy Simulation for Incompressible Flows

Large Eddy Simulation for Incompressible Flows PDF Author: P. Sagaut
Publisher: Springer Science & Business Media
ISBN: 9783540263449
Category : Computers
Languages : en
Pages : 600

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Book Description
First concise textbook on Large-Eddy Simulation, a very important method in scientific computing and engineering From the foreword to the third edition written by Charles Meneveau: "... this meticulously assembled and significantly enlarged description of the many aspects of LES will be a most welcome addition to the bookshelves of scientists and engineers in fluid mechanics, LES practitioners, and students of turbulence in general."

Large Eddy Simulation for Incompressible Flows

Large Eddy Simulation for Incompressible Flows PDF Author: P. Sagaut
Publisher: Springer Science & Business Media
ISBN: 3662046954
Category : Science
Languages : en
Pages : 437

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Book Description
First concise textbook on Large-Eddy Simulation, a very important method in scientific computing and engineering From the foreword to the third edition written by Charles Meneveau: "... this meticulously assembled and significantly enlarged description of the many aspects of LES will be a most welcome addition to the bookshelves of scientists and engineers in fluid mechanics, LES practitioners, and students of turbulence in general."

Large Eddy Simulation for Compressible Flows

Large Eddy Simulation for Compressible Flows PDF Author: Eric Garnier
Publisher: Springer Science & Business Media
ISBN: 9048128196
Category : Science
Languages : en
Pages : 280

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Book Description
This book addresses both the fundamentals and the practical industrial applications of Large Eddy Simulation (LES) in order to bridge the gap between LES research and the growing need to use it in engineering modeling.

Implicit Large Eddy Simulation

Implicit Large Eddy Simulation PDF Author: Fernando F. Grinstein
Publisher: Cambridge University Press
ISBN: 9780521869829
Category : Technology & Engineering
Languages : en
Pages : 578

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Book Description
The numerical simulation of turbulent flows is a subject of great practical importance to scientists and engineers. The difficulty in achieving predictive simulations is perhaps best illustrated by the wide range of approaches that have been developed and are still being used by the turbulence modeling community. In this book the authors describe one of these approaches, Implicit Large Eddy Simulation (ILES). ILES is a relatively new approach that combines generality and computational efficiency with documented success in many areas of complex fluid flow. This book synthesizes the theoretical basis of the ILES methodology and reviews its accomplishments. ILES pioneers and lead researchers combine here their experience to present a comprehensive description of the methodology. This book should be of fundamental interest to graduate students, basic research scientists, as well as professionals involved in the design and analysis of complex turbulent flows.