Download or read book Large Eddy Simulation of a Turbulent Channel Flow with a Rib roughened Wall written by Ning Meng and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Eddy Simulation of a Rib Roughened Turbulent Channel Flow with Heat Transfer and Property Variations written by Ning Meng and published by . This book was released on 2001 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent channel flow with a rib-roughened wall has been computed with constant heating rate using large eddy simulation. An implicit, second order accurate finite volume scheme was used to solve the time dependent filtered set of equations to determine large eddies, while a dynamic subgrid-scale model was used to account for the subgrid scale effects. A dynamic Prandtl number was introduced to calculate subgrid scale heat transfer. The effects of strong heating on the rib-roughened wall were investigated and Nusselt numbers were computed and compared with experimental data. The instantaneous plots revealed the influence of turbulent heat transfer on velocity, temperature and vorticity in this particular geometry.
Download or read book Direct and Large Eddy Simulation XII written by Manuel García-Villalba and published by Springer Nature. This book was released on 2020-05-09 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gathers the proceedings of the 12th instalment in the bi-annual Workshop series on Direct and Large Eddy Simulation (DLES), which began in 1994 and focuses on modern techniques used to simulate turbulent flows based on the partial or full resolution of the instantaneous turbulent flow structure. With the rapidly expanding capacities of modern computers, this approach has attracted more and more interest over the years and will undoubtedly be further enhanced and applied in the future. Hybrid modelling techniques based on a combination of LES and RANS approaches also fall into this category and are covered as well. The goal of the Workshop was to share the state of the art in DNS, LES and related techniques for the computation and modelling of turbulent and transitional flows. The respective papers highlight the latest advances in the prediction, understanding and control of turbulent flows in academic and industrial applications.
Download or read book Direct and Large Eddy Simulation VIII written by Hans Kuerten and published by Springer Science & Business Media. This book was released on 2011-10-05 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume continues previous DLES proceedings books, presenting modern developments in turbulent flow research. It is comprehensive in its coverage of numerical and modeling techniques for fluid mechanics. After Surrey in 1994, Grenoble in 1996, Cambridge in 1999, Enschede in 2001, Munich in 2003, Poitiers in 2005, and Trieste in 2009, the 8th workshop, DLES8, was held in Eindhoven, The Netherlands, again under the auspices of ERCOFTAC. Following the spirit of the series, the goal of this workshop is to establish a state-of-the-art of DNS and LES techniques for the computation and modeling of transitional/turbulent flows covering a broad scope of topics such as aerodynamics, acoustics, combustion, multiphase flows, environment, geophysics and bio-medical applications. This gathering of specialists in the field was a unique opportunity for discussions about the more recent advances in the prediction, understanding and control of turbulent flows in academic or industrial situations.
Download or read book Large Eddy Simulations of Turbulence written by M. Lesieur and published by Cambridge University Press. This book was released on 2005-08-22 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large-Eddy Simulations of Turbulence is a reference for LES, direct numerical simulation and Reynolds-averaged Navier-Stokes simulation.
Download or read book Large Eddy Simulation for Incompressible Flows written by P. Sagaut and published by Springer Science & Business Media. This book was released on 2006 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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."
Download or read book Large Eddy Simulation of Turbulent Flows with Variable Property Heat Transfer Using a Compressible Finite Volume Formulation written by Lyle Douglas Dailey and published by . This book was released on 1997 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: The LES formulation provided excellent agreement with DNS and experimental results for simple turbulent flows (i.e. homogeneous, isotropic, decaying turbulence and smooth wall channel flows). For the constant heat flux channel flows, high heating tended to reduce the velocity fluctuations, while high cooling tended to promote the fluctuations. The mean and fluctuation velocity profiles collapsed towards the incompressible results when normalized by local properties, as opposed to wall values. The temperature fluctuation profiles were largely independent of the heating rate when normalized BV the wall-to-bulk temperature difference. Problems related to significant odd-even decoupling, grid distributions, and SGS modeling were identified for the rib-roughened channel.
Download or read book Direct and Large Eddy Simulation XIII written by Cristian Marchioli and published by Springer Nature. This book was released on 2023-11-15 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the diverse and cutting-edge research presented at the 13th ERCOFTAC Workshop on Direct and Large Eddy Simulation. The first section of the book focuses on Aerodynamics/Aeroacoustics, comprising eight papers that delve into the intricate relationship between fluid flow and aerodynamic performance. The second section explores the dynamics of Bluff/Moving Bodies through four insightful papers. Bubbly Flows, the subject of the third section, is examined through four papers. Moving on, the fourth section is dedicated to Combustion and Reactive Flows, presenting two papers that focus on the complex dynamics of combustion processes and the interactions between fluids and reactive species. Convection and Heat/Mass Transfer are the central themes of the fifth section, which includes three papers. These contributions explore the fundamental aspects of heat and mass transfer in fluid flows, addressing topics such as convective heat transfer, natural convection, and mass transport phenomena. The sixth section covers Data Assimilation and Uncertainty Quantification, featuring two papers that highlight the importance of incorporating data into fluid dynamic models and quantifying uncertainties associated with these models. The subsequent sections encompass a wide range of topics, including Environmental and Industrial Applications, Flow Separation, LES Fundamentals and Modelling, Multiphase Flows, and Numerics and Methodology. These sections collectively present a total of 23 papers that explore different facets of fluid dynamics, contributing to the advancement of the field and its practical applications.
Download or read book Direct and Large Eddy Simulation I written by Peter R. Voke and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is a truism that turbulence is an unsolved problem, whether in scientific, engin eering or geophysical terms. It is strange that this remains largely the case even though we now know how to solve directly, with the help of sufficiently large and powerful computers, accurate approximations to the equations that govern tur bulent flows. The problem lies not with our numerical approximations but with the size of the computational task and the complexity of the solutions we gen erate, which match the complexity of real turbulence precisely in so far as the computations mimic the real flows. The fact that we can now solve some turbu lence in this limited sense is nevertheless an enormous step towards the goal of full understanding. Direct and large-eddy simulations are these numerical solutions of turbulence. They reproduce with remarkable fidelity the statistical, structural and dynamical properties of physical turbulent and transitional flows, though since the simula tions are necessarily time-dependent and three-dimensional they demand the most advanced computer resources at our disposal. The numerical techniques vary from accurate spectral methods and high-order finite differences to simple finite-volume algorithms derived on the principle of embedding fundamental conservation prop erties in the numerical operations. Genuine direct simulations resolve all the fluid motions fully, and require the highest practical accuracy in their numerical and temporal discretisation. Such simulations have the virtue of great fidelity when carried out carefully, and repre sent a most powerful tool for investigating the processes of transition to turbulence.
Download or read book Direct and Large Eddy Simulation XI written by Maria Vittoria Salvetti and published by Springer. This book was released on 2019-02-02 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Direct and Large Eddy Simulation of Turbulence written by NA Schumann and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains papers presented to a EUROMECH-Colloquium held in Munich, September 30 to October 2, 1985. The Colloquium is number 199 in a series of colloquia inaugurated by the European Mechanics Committee. The meeting was jointly organized by the 'Lehrstuhl fur Stromungsmechanik' at the 'Technische Universitat Munchen' and the 'Institut fur Physik der Atmosphare' of the 'Deutsche Forschungs- und Versuchsanstalt fur Luft- und Raumfahrt' (DFVLR) in Oberpfaffenhofen. 'Direct' and 'large eddy simulation' are terms which denote two closely con nected methods of turbulence research. In a 'direct simulation' (DS), turbu lent motion is simulated by numerically integrating the Navier-Stokes equations in three-dimensional space and as a function of time. Besides ini tial and boundary conditions no physical simplifications are involved. Com puter resources limit the resolution in time and space, though simulations with an order of one million discrete points in space are feasible. The simu lated flow fields can be considered as true realizations of turbulent flow fields and analysed to answer questions on the basic behaviour of turbulence. Direct simulations are valid as long as all the excited scales remain within the band of resolved scales. This means that viscosity must be strong enough to damp out the not resolved scales or the simulation is restricted to a lim ited integration-time interval only. In summary, DS provides a tool to investigate turbulent motions from first principles at least for a finite band of scales.
Download or read book Large Eddy Simulation of Turbulent Flows with Property Variations Rotation and Complex Geometry written by Ning Meng and published by . This book was released on 2000 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: The mean and fluctuation velocity profiles approach the incompressible results when normalized by local properties, as opposed to wall values. Spanwise system rotation is found to suppress turbulent velocity fluctuations and shear stresses near the stable side of the channel, but enhance the fluctuations and shear stresses near the unstable side. Turbulent temperature fluctuations and turbulent heat flux decreased near the stable side of the channel, but increased near the unstable side of the channel. In the case of the rib-roughened channel flow, a small recirculation zone before the rib and a larger recirculation zone after the rib are observed. Increased turbulent fluctuations and heat transfer are found around the rib.
Download or read book Large Eddy Simulation for Compressible Flows written by Eric Garnier and published by Springer Science & Business Media. This book was released on 2009-08-11 with total page 280 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Mathematics of Large Eddy Simulation of Turbulent Flows written by Luigi Carlo Berselli and published by Springer Science & Business Media. This book was released on 2006 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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
Download or read book Large Eddy Interactions in a Turbulent Channel Flow written by and published by . This book was released on 1985 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Eddy Simulation of Compressible Turbulent Channel and Annular Pipe Flows with System and Wall Rotations written by Joon Sang Lee and published by . This book was released on 2004 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt: The compressible filtered Navier-Stokes equations were solved using a second order accurate finite volume method with low Mach number preconditioning. A dynamic subgrid-scale stress model accounted for the subgrid-scale turbulence. The study focused on the effects of buoyancy and rotation on the structure of turbulence and transport processes including heat transfer. Several different physical arrangements were studied as outlined below. The effects of buoyancy were first studied in a vertical channel using large eddy simulation (LES). The walls were maintained at constant temperatures, one heated and the other cooled. Results showed that aiding and opposing buoyancy forces emerge near the heated and cooled walls, respectively. In the aiding flow, the turbulent intensities and heat transfer were suppressed at large values of Grashof number. In the opposing flow, however, turbulence was enhanced with increased velocity fluctuations. Another buoyancy study considered turbulent flow in a vertically oriented annulus. Isoflux wall boundary conditions with low and high heating were imposed on the inner wall while the outer wall was adiabatic. The results showed that the strong heating and buoyancy force caused distortions of the flow structure resulting in reduction of turbulent intensities, shear stress, and turbulent heat flux, particularly near the heated wall. Flow in an annular pipe with and without an outer wall rotation about its axis was first investigated at moderate Reynolds numbers. When the outer pipe wall was rotated, a significant reduction of turbulent kinetic energy was realized near the rotating wall. Secondly, a large eddy simulation has been performed to investigate the effect of swirl on the heat and momentum transfer in an annular pipe flow with a rotating inner wall. The simulations indicated that the Nusselt number and the wall friction coefficient increased with increasing rotation speed of the wall. It was also observed that the axial velocity profile became flattened and turbulent intensities were enhanced due to swirl. As a part of the study of rotation effects, a large eddy simulation of a rotating ribbed channel flow with the heat transfer was investigated. The rotation axis was parallel to the spanwise direction of the parallel plate channel. Uniform heat flux was applied to the channel for two rates of rotation. The results showed that near the stable (leading) side, the turbulent intensities and heat transfer were suppressed, but turbulence was enhanced with increasing shear stress and turbulent kinetic energy near the unstable (trailing) side.
Download or read book Large Eddy Simulation of Wall Bounded Turbulent Flows with Heat Transfer written by Yang Liu and published by . This book was released on 2002 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis work, large eddy simulation was used to study a variety of wall-bounded turbulent flows using a compressible finite volume formulation. Subgrid scale terms in both momentum and energy equations were modeled dynamically. Furthermore, due to the inhomogeniety of wall-bounded flows, the model was further localized to better represent the physics of the problem. The model was first applied to study the incompressible turbulent flow through a duct with square cross-section. Mean flow, law of the wall, and turbulence statistics were compared with the benchmark results of direct numerical simulation and excellent agreement was achieved. The secondary flow in the cross-section was captured. It is composed of four pairs of counter-rotating cells. The interaction between mean and secondary flow fields creates some important features and they were studied in this work. Based on incompressible duct flow, system rotation was applied to investigate the effects of rotation on the turbulent flow field. The system rotation was found to reduce turbulence level on the leading side, while increase turbulence level on the trailing side. Because of the rotation, the secondary flow field in non-rotating duct was found to be diminished at weaker rotation and even eliminated at stronger rotation. Instead, a pair of counter rotating cells called Taylor-Görtler vortices, as well as the Taylor-Proudman regime, was found to exist in the cross-section, which is consistent with the results of the literature. Large eddy simulation was also applied to investigate the effects of ribs and system rotation on heat transfer in a channel. It was found that a rib creates recirculation zones near the rib. The turbulence level is at its maximum near the ribs. The existence of ribs enhances heat transfer significantly over the plane channel, as well as creates low-heat-transfer-coefficient region in the recirculation zones. This means a balance is needed between global enhancement and local suppression. With system rotation, heat transfer is greatly enhanced on the trailing side, while significantly reduced on the leading side.
