Large-eddy Simulation of Turbulent Flow Over Rough Surfaces PDF Download

Author: Jie Cui
Publisher:
ISBN:
Category : Turbulence
Languages : en
Pages : 486

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Book Description

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.

Author: Trong T. Bui
Publisher:
ISBN:
Category : Parallel computers
Languages : en
Pages : 28

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Book Description

Author: Maria Vittoria Salvetti
Publisher: Springer
ISBN: 3030049159
Category : Technology & Engineering
Languages : en
Pages : 608

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Book Description
This book gathers the proceedings of the 11th workshop on Direct and Large Eddy Simulation (DLES), which was held in Pisa, Italy in May 2017. The event focused on modern techniques for simulating turbulent flows based on the partial or full resolution of the instantaneous turbulent flow structures, as Direct Numerical Simulation (DNS), Large-Eddy Simulation (LES) or hybrid models based on a combination of LES and RANS approaches. In light of the growing capacities of modern computers, these approaches have been gaining more and more interest over the years and will undoubtedly be developed and applied further. The workshop offered a unique opportunity to establish a state-of-the-art of DNS, LES and related techniques for the computation and modeling of turbulent and transitional flows and to discuss about recent advances and applications. This volume contains most of the contributed papers, which were submitted and further reviewed for publication. They cover advances in computational techniques, SGS modeling, boundary conditions, post-processing and data analysis, and applications in several fields, namely multiphase and reactive flows, convection and heat transfer, compressible flows, aerodynamics of airfoils and wings, bluff-body and separated flows, internal flows and wall turbulence and other complex flows.

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."

Author: Johan Meyers
Publisher: Springer Science & Business Media
ISBN: 1402085788
Category : Science
Languages : en
Pages : 390

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Book Description
Computational resources have developed to the level that, for the first time, it is becoming possible to apply large-eddy simulation (LES) to turbulent flow problems of realistic complexity. Many examples can be found in technology and in a variety of natural flows. This puts issues related to assessing, assuring, and predicting the quality of LES into the spotlight. Several LES studies have been published in the past, demonstrating a high level of accuracy with which turbulent flow predictions can be attained, without having to resort to the excessive requirements on computational resources imposed by direct numerical simulations. However, the setup and use of turbulent flow simulations requires a profound knowledge of fluid mechanics, numerical techniques, and the application under consideration. The susceptibility of large-eddy simulations to errors in modelling, in numerics, and in the treatment of boundary conditions, can be quite large due to nonlinear accumulation of different contributions over time, leading to an intricate and unpredictable situation. A full understanding of the interacting error dynamics in large-eddy simulations is still lacking. To ensure the reliability of large-eddy simulations for a wide range of industrial users, the development of clear standards for the evaluation, prediction, and control of simulation errors in LES is summoned. The workshop on Quality and Reliability of Large-Eddy Simulations, held October 22-24, 2007 in Leuven, Belgium (QLES2007), provided one of the first platforms specifically addressing these aspects of LES.

Author: Zeng Zhang
Publisher:
ISBN:
Category :
Languages : en
Pages : 102

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Book Description
Open channels often have a rough bed surface. A good understanding of the characteristics of water flow over the rough bed is important for many applications in hydraulic engineering. Examples include investigations of the re-suspension and transport of contaminated bed materials, channel erosion, and the effectiveness of dissipating excessive flow energy. In this thesis, the rough surface was created by placing transverse bars at a flat channel-bed in one case and cubes in the other case, and the velocity field of rough-surface flow was computed through large eddy simulations (LES). This thesis aims to evaluate suitable computing strategies, validate computational results using available experimental data, and explore the detailed structures of near-bed flow. On the basis of the bars centre-to-centre spacing, , relative to their vertical dimension, k, studies of the rough-surface flow classify the rough elements as k-type and d-type ribs. Previous experimental studies of the rough-surface flow have produced some measurements of flow velocities, provided assessments of the suitability of existing methods for determining the shear velocity, and comparisons of characteristics between flow over d-type ribs and that over smooth walls, as well as between flow over ribs and that over transverse rows of staggered cubes. The main findings were that similarities existed in the outer layer between flow over three-dimensional roughness and flow over smooth walls. Some previous numerical studies introduced a form-drag term in the momentum equation to indirectly allow for the effect of roughness on the flow. Other numerical studies used obstacles as bed roughness elements, and applied non-slip conditions at their surfaces. A significant limitation of the previous studies is the use of conditions of fully developed boundary layer flow with zero-pressure gradient. This would be very approximate for water flows in shallow open channels. The canonical turbulent boundary layers are not expected to be valid, because the boundary layer thickness is a significant fraction of the depth of flow. Further investigations of the flow characteristics are needed. The large eddy simulations reported in this thesis capture the flow characteristics in the near-bed region. They gave numerical predictions of the flow field over transverse bars in shallow open channels at a range of /k ratios. The predictions provide accurate horizontal turbulence intensities, and horizontal velocity. It seems that large eddy simulations produce accurate flow characteristics in the streamwise direction, but less accurate results in the vertical direction. A plausible reason is the side wall effects. It is challenging to realistically capture secondary flow that creates transverse vortices in the transverse direction on both sides of the channel. These vortices cause upward motions at the middle of the channel. The power spectrum density (PSD) curves for all the runs show characteristics of energy cascade that are consistent with the results reported in the literature (Rodi, 2017), in particular the energy distribution for the inertia subrange. It has been concluded that: 1) an increase in the n/k ratio leads to a decrease in the region of reverse flow within the cavity, and an increase in the shear stress on the upstream face of transverse bars; 2) in the case of flow over staggered cubes, they tend to restrict reverse flow, and cause the shear stress at the upstream edge of the cubes to increase; 3) it is suitable to apply cyclic boundary conditions in both the transverse and streamwise directions in simulations of fully developed flow.

Author: Volker John
Publisher: Springer Science & Business Media
ISBN: 3642186823
Category : Technology & Engineering
Languages : en
Pages : 270

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Book Description
Large eddy simulation (LES) seeks to simulate the large structures of a turbulent flow. This is the first monograph which considers LES from a mathematical point of view. It concentrates on LES models for which mathematical and numerical analysis is already available and on related LES models. Most of the available analysis is given in detail, the implementation of the LES models into a finite element code is described, the efficient solution of the discrete systems is discussed and numerical studies with the considered LES models are presented.

Author: Luigi Carlo Berselli
Publisher: Springer Science & Business Media
ISBN: 9783540263166
Category : Computers
Languages : en
Pages : 378

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Book Description
The LES-method is rapidly developing in many practical applications in engineering The mathematical background is presented here for the first time in book form by one of the leaders in the field

Author: Pierre Sagaut
Publisher: Springer Science & Business Media
ISBN: 3662044161
Category : Science
Languages : en
Pages : 326

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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."