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Large Eddy Simulations Of Complex Turbulent Flows Using Immersed Boundary Method
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Book Synopsis Large Eddy Simulations of Complex Turbulent Flows Using Immersed Boundary Method by : Mayank Tyagi
Download or read book Large Eddy Simulations of Complex Turbulent Flows Using Immersed Boundary Method written by Mayank Tyagi and published by . This book was released on 2001 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large eddy simulations (LES) are performed for two representative complex geometry problems of particular interest to turbomachinery flows, First problem studied is the flow field inside a trapped-vortex combustor. Second problem is the unsteady interaction of rotor blade with stator blade wake field. The representation of complex geometry is done using immersed boundary method (IBM). Two different implementations are presented for the body force terms.
Book Synopsis Large Eddy Simulations of Turbulent Flows on Graphics Processing Units: Application to Film-cooling Flows by : Aaron F. Shinn
Download or read book Large Eddy Simulations of Turbulent Flows on Graphics Processing Units: Application to Film-cooling Flows written by Aaron F. Shinn and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Fluid Dynamics (CFD) simulations can be very computationally expensive, especially for Large Eddy Simulations (LES) and Direct Numerical Simulations (DNS) of turbulent flows. In LES the large, energy containing eddies are resolved by the computational mesh, but the smaller (sub-grid) scales are modeled. In DNS, all scales of turbulence are resolved, including the smallest dissipative (Kolmogorov) scales. Clusters of CPUs have been the standard approach for such simulations, but an emerging approach is the use of Graphics Processing Units (GPUs), which deliver impressive computing performance compared to CPUs. Recently there has been great interest in the scientific computing community to use GPUs for general-purpose computation (such as the numerical solution of PDEs) rather than graphics rendering. To explore the use of GPUs for CFD simulations, an incompressible Navier-Stokes solver was developed for a GPU. This solver is capable of simulating unsteady laminar flows or performing a LES or DNS of turbulent flows. The Navier-Stokes equations are solved via a fractional-step method and are spatially discretized using the finite volume method on a Cartesian mesh. An immersed boundary method based on a ghost cell treatment was developed to handle flow past complex geometries. The implementation of these numerical methods had to suit the architecture of the GPU, which is designed for massive multithreading. The details of this implementation will be described, along with strategies for performance optimization. Validation of the GPU-based solver was performed for fundamental bench-mark problems, and a performance assessment indicated that the solver was over an order-of-magnitude faster compared to a CPU. The GPU-based Navier-Stokes solver was used to study film-cooling flows via Large Eddy Simulation. In modern gas turbine engines, the film-cooling method is used to protect turbine blades from hot combustion gases. Therefore, understanding the physics of this problem as well as techniques to improve it is important. Fundamentally, a film-cooling configuration is an inclined cooling jet in a hot cross-flow. A known problem in the film-cooling method is jet lift-off, where the jet of coolant moves away from the surface to be cooled due to mutual vortex induction by the counter-rotating vortex pair embedded in the jet, resulting in decreased cooling at the surface. To counteract this, a micro-ramp vortex generator was added downstream of the film-cooling jet, which generated near-wall counter-rotating vortices of opposite sense to the vortex pair in the jet. It was found that the micro-ramp vortices created a downwash effect toward the wall, which helped entrain coolant from the jet and transport it to the wall, resulting in better cooling. Results are reported using two film-cooling configurations, where the primary difference is the way the jet exit boundary conditions are prescribed. In the first configuration, the jet is prescribed using a precursor simulation and in the second the jet is modeled using a plenum/pipe configuration. The latter configuration was designed based on previous wind tunnel experiments at NASA Glenn Research Center, and the present results were meant to supplement those experiments.
Book Synopsis Direct and Large-Eddy Simulation XI by : Maria Vittoria Salvetti
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.
Book Synopsis Large Eddy Simulation for Incompressible Flows by : P. Sagaut
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."
Book Synopsis Large Eddy Simulation for Compressible Flows by : Eric Garnier
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.
Book Synopsis Complex Effects in Large Eddy Simulations by : Stavros Kassinos
Download or read book Complex Effects in Large Eddy Simulations written by Stavros Kassinos and published by Springer Science & Business Media. This book was released on 2007-07-16 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: The field of Large Eddy Simulations is reaching a level of maturity that brings this approach to the mainstream of engineering computations, while it opens opportunities and challenges. The main objective of this volume is to bring together leading experts in presenting the state-of-the-art and emerging approaches for treating complex effects in LES. A common theme throughout is the role of LES in the context of multiscale modeling and simulation.
Book Synopsis Large Eddy Simulation of Turbulent Flow Over a Rough Bed Using the Immersed Boundary Method by : Sandeep Kumar Bomminayuni
Download or read book Large Eddy Simulation of Turbulent Flow Over a Rough Bed Using the Immersed Boundary Method written by Sandeep Kumar Bomminayuni and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Study of turbulent flow over a rough bed is highly important due to its numerous applications in the areas of sediment transport and pollutant discharge in streams, rivers and channels. Over the past few decades, many experimental studies have been conducted in this respect to understand the underlying phenomenon. However, there is a scarcity in the number of computational studies conducted on this topic. Therefore, a Large Eddy Simulation (LES) of turbulent flow over a rough channel bed was conducted to contribute further understanding of the influence of bed roughness on turbulent flow properties. For this purpose, an efficient, second order accurate 'immersed boundary method' was implemented into the LES code Hydro3d-GT, and validated for flow past bluff bodies. LES results from the present study showed excellent agreement with previous experimental studies on flow over rough beds. An in-depth analysis of time varying turbulent quantities (like the velocity fluctuations) revealed the presence of coherent structures in the flow. Also, a three dimensional visualization of the turbulent structures provided a good picture of the flow, especially in the near bed region, which is quite difficult to accomplish using experimental studies.
Book Synopsis Direct and Large-Eddy Simulation IV by : Bernard Geurts
Download or read book Direct and Large-Eddy Simulation IV written by Bernard Geurts and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 543 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the 2001 DLES4 workshop. It describes and discusses state-of-the-art modeling and simulation approaches for complex flows. Fundamental turbulence and modeling issues but also elements from modern numerical analysis are at the heart of this field of interest.
Book Synopsis Large Eddy Simulation of Complex Engineering and Geophysical Flows by : Boris Galperin
Download or read book Large Eddy Simulation of Complex Engineering and Geophysical Flows written by Boris Galperin and published by Cambridge University Press. This book was released on 1993-11-26 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: Originally published in 1993, this book was the first to offer a comprehensive review of large eddy simulations (LES) - the history, state of the art, and promising directions for research. Among topics covered are fundamentals of LES; LES of incompressible, compressible, and reacting flows; LES of atmospheric, oceanic, and environmental flows; and LES and massivelt parallel computing. The book grew out of an international workshop that, for the first time, brought together leading researchers in engineering and geophysics to discuss developments and applications of LES models in their respective fields. It will be of value to anyone with an interest in turbulence modelling.
Author :Luigi Carlo Berselli Publisher :Springer Science & Business Media ISBN 13 :9783540263166 Total Pages :378 pages Book Rating :4.2/5 (631 download)
Book Synopsis Mathematics of Large Eddy Simulation of Turbulent Flows by : Luigi Carlo Berselli
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
Book Synopsis Direct and Large Eddy Simulation XII by : Manuel García-Villalba
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.
Book Synopsis Simulation of Stratified Turbulent Flows in Complex Geometry by : Narsimha Reddy Rapaka
Download or read book Simulation of Stratified Turbulent Flows in Complex Geometry written by Narsimha Reddy Rapaka and published by . This book was released on 2015 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Direct and Large Eddy Simulation approaches are used to study internal tide generation and turbulence at a model topography. A three dimensional finite difference code using an immersed boundary method is developed to simulate stratified turbulent flows over complex geometry on a Cartesian grid. The thesis is comprised of two phases. In the first phase, a mixed spectral/finite difference code is used to solve the governing equations in generalized coordinates. Direct and large eddy simulations are performed using a body fitted grid (BFG) to study the internal waves generated by the oscillation of a barotropic tide over a model ridge of triangular shape. The objective is to assess the role of nonlinear interactions including turbulence in situations with low tidal excursion number. The criticality parameter, defined as the ratio of the topographic slope to the characteristic slope of the tidal rays, is varied from subcritical to supercritical values. The barotropic tidal forcing is also systematically increased. In laminar flow at low forcing, numerical results of the energy conversion agree well compared to linear theory in subcritical and supercritical cases but not at critical slope angle. In critical and supercritical cases with higher forcing, there are convective overturns, turbulence and significant reduction (as much as 25%) of the radiated wave flux with respect to laminar flow results. The phase dependence of turbulence within a tidal cycle is examined and found to differ substantially between the ridge slope and the ridge top where the beams from the two sides cross. In the second phase, a sharp-interface Immersed Boundary Method (IBM) is developed to simulate high Reynolds number density-stratified turbulent flows in complex geometry. The basic numerical scheme corresponds to a central second-order finite difference method, third-order Runge-Kutta integration for the advective terms and an alternating direction implicit (ADI) scheme for the viscous and diffusive terms. Both direct numerical simulation (DNS) and large eddy simulation (LES) approaches are considered. The focus is on accurate computation of the internal gravity wave field and turbulence near an underwater obstacle in a model problem where a tide oscillates over the obstacle. Methods to enhance the mass conservation and numerical stability of the solver to simulate high Reynolds number flows are discussed. The solver is validated using Direct Numerical Simulations (DNS) of channel flow with and without stratification, and tidal flow over a laboratory-scale (order of few meters) smoothed triangular ridge. The results including baroclinic energy flux, mean flow properties and turbulent kinetic energy agree reasonably well with our previous results obtained using a body-fitted grid (BFG). The deviation of IBM results from BFG results is found to increase with increasing steepness of the topography relative to the internal wave propagation angle. LES is performed on a large scale ridge, of the order of few kilometers in length, at significantly larger Reynolds number. A non-linear drag law is utilized to parameterize turbulent losses due to bottom friction. The large scale problem exhibits qualitatively similar behavior to the laboratory scale problem with some differences: slightly larger intensification of the boundary flow and somewhat higher nondimensional values for conversion, baroclinic wave flux and turbulent kinetic energy. The phasing of wave breaking and turbulence exhibits little difference between small and large scale obstacles. We conclude that IBM is a viable approach to the simulation of internal waves and turbulence in high Reynolds number stratified flows over topography.
Book Synopsis Large-Eddy Simulations of Turbulence by : M. Lesieur
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.
Book Synopsis Implicit Large Eddy Simulation by : Fernando F. Grinstein
Download or read book Implicit Large Eddy Simulation written by Fernando F. Grinstein and published by Cambridge University Press. This book was released on 2007-07-30 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Immersed Boundary Method by : Somnath Roy
Download or read book Immersed Boundary Method written by Somnath Roy and published by Springer Nature. This book was released on 2020-05-15 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the emerging applications of immersed boundary (IB) methods in computational mechanics and complex CFD calculations. It discusses formulations of different IB implementations and also demonstrates applications of these methods in a wide range of problems. It will be of special value to researchers and engineers as well as graduate students working on immersed boundary methods, specifically on recent developments and applications. The book can also be used as a supplementary textbook in advanced courses in computational fluid dynamics.
Book Synopsis Direct and Large-Eddy Simulation I by : Peter R. Voke
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.
Book Synopsis Modeling Approaches and Computational Methods for Particle-laden Turbulent Flows by : Shankar Subramaniam
Download or read book Modeling Approaches and Computational Methods for Particle-laden Turbulent Flows written by Shankar Subramaniam and published by Academic Press. This book was released on 2022-10-20 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modelling Approaches and Computational Methods for Particle-laden Turbulent Flows introduces the principal phenomena observed in applications where turbulence in particle-laden flow is encountered while also analyzing the main methods for analyzing numerically. The book takes a practical approach, providing advice on how to select and apply the correct model or tool by drawing on the latest research. Sections provide scales of particle-laden turbulence and the principal analytical frameworks and computational approaches used to simulate particles in turbulent flow. Each chapter opens with a section on fundamental concepts and theory before describing the applications of the modelling approach or numerical method. Featuring explanations of key concepts, definitions, and fundamental physics and equations, as well as recent research advances and detailed simulation methods, this book is the ideal starting point for students new to this subject, as well as an essential reference for experienced researchers. - Provides a comprehensive introduction to the phenomena of particle laden turbulent flow - Explains a wide range of numerical methods, including Eulerian-Eulerian, Eulerian-Lagrange, and volume-filtered computation - Describes a wide range of innovative applications of these models
