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The Local Variational Multiscale Method For Turbulence Simulation
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Book Synopsis The Local Variational Multiscale Method for Turbulence Simulation by :
Download or read book The Local Variational Multiscale Method for Turbulence Simulation written by and published by . This book was released on 2005 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate and efficient turbulence simulation in complex geometries is a formidable chal-lenge. Traditional methods are often limited by low accuracy and/or restrictions to simplegeometries. We explore the merger of Discontinuous Galerkin (DG) spatial discretizationswith Variational Multi-Scale (VMS) modeling, termed Local VMS (LVMS), to overcomethese limitations. DG spatial discretizations support arbitrarily high-order accuracy on un-structured grids amenable for complex geometries. Furthermore, high-order, hierarchicalrepresentation within DG provides a natural framework fora prioriscale separation crucialfor VMS implementation. We show that the combined benefits of DG and VMS within theLVMS method leads to promising new approach to LES for use in complex geometries. The efficacy of LVMS for turbulence simulation is assessed by application to fully-developed turbulent channelflow. First, a detailed spatial resolution study is undertakento record the effects of the DG discretization on turbulence statistics. Here, the localhp refinement capabilites of DG are exploited to obtain reliable low-order statistics effi-ciently. Likewise, resolution guidelines for simulating wall-bounded turbulence using DGare established. We also explore the influence of enforcing Dirichlet boundary conditionsindirectly through numericalfluxes in DG which allows the solution to jump (slip) at thechannel walls. These jumps are effective in simulating the influence of the wall commen-surate with the local resolution and this feature of DG is effective in mitigating near-wallresolution requirements. In particular, we show that by locally modifying the numericalviscousflux used at the wall, we are able to regulate the near-wall slip through a penaltythat leads to improved shear-stress predictions. This work, demonstrates the potential ofthe numerical viscousflux to act as a numerically consistent wall-model and this successwarrents future research. As in any high-order numerical method some mechanism is required to control aliasingeffects due to nonlinear interactions and to ensure nonlinear stability of the method. Inthis context, we evaluate the merits of two approaches to de-aliasing -- spectralfilteringand polynomial dealiasing. While both approaches are successful, polynomial-dealiasingis found to be better suited for use in large-eddy simulation. Finally, results using LVMSare reported and show good agreement with reference direct numerical simulation therebydemonstrating the effectiveness of LVMS for wall-bounded turbulence. This success pavesthe way for future applications of LVMS to more complex turbulentflows. 3.
Book Synopsis A Variational Multiscale Method for Turbulent Flow Simulation with Adaptive Large Scale Space by : Volker John
Download or read book A Variational Multiscale Method for Turbulent Flow Simulation with Adaptive Large Scale Space written by Volker John and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Numerical Analysis of a Variational Multiscale Method for Turbulence by : Songül Kaya Merdan
Download or read book Numerical Analysis of a Variational Multiscale Method for Turbulence written by Songül Kaya Merdan and published by LAP Lambert Academic Publishing. This book was released on 2011-10 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite efforts of more than centuries, turbulence phenomena is categorized as an unsolved problem. Turbulence is part of everyday's life. The majority of flows of industrial and technological applications are turbulent; natural flows are invariably so. There are many important and interesting physical phenomena which are connected with turbulent flows. Turbulence is observed in natural and engineering applications such as in weather prediction, air pollution, water pollution, aerodynamics and heat exchangers. This work considers an accurate and reliable solutions of turbulent flows. It is concerned with one of the most promising approaches to the numerical simulation of turbulent flows, the subgrid eddy viscosity models. We analyze both continuous and discontinuous finite element approximation of the new subgrid eddy viscosity model. This approach has the advantage that the diffusivity is introduced only on the small scales of the flow. Numerical test shows the new stabilization technique is robust and efficient in solving Navier-Stokes equations for a wide range of Reynolds numbers.
Book Synopsis Turbulence Modeling by a Projection-based Variational Multiscale Method for Incompressible Flow Problems by : Lars Röhe
Download or read book Turbulence Modeling by a Projection-based Variational Multiscale Method for Incompressible Flow Problems written by Lars Röhe and published by . This book was released on 2011 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Geometric Modeling with Splines by : Elaine Cohen
Download or read book Geometric Modeling with Splines written by Elaine Cohen and published by CRC Press. This book was released on 2001-07-18 with total page 638 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by researchers who have helped found and shape the field, this book is a definitive introduction to geometric modeling. The authors present all of the necessary techniques for curve and surface representations in computer-aided modeling with a focus on how the techniques are used in design. They achieve a balance between mathematical rigor
Book Synopsis Multiscale and Multiresolution Approaches in Turbulence by : Pierre Sagaut
Download or read book Multiscale and Multiresolution Approaches in Turbulence written by Pierre Sagaut and published by World Scientific. This book was released on 2013 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book aims to provide the reader with an updated general presentation of multiscale/multiresolution approaches in turbulent flow simulations. All modern approaches (LES, hybrid RANS/LES, DES, SAS) are discussed and recast in a global comprehensive framework. Both theoretical features and practical implementation details are addressed. Some full scale applications are described, to provide the reader with relevant guidelines to facilitate a future use of these methods.
Book Synopsis Multiscale Methods in Computational Mechanics by : René de Borst
Download or read book Multiscale Methods in Computational Mechanics written by René de Borst and published by Springer Science & Business Media. This book was released on 2010-10-09 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work gives a modern, up-to-date account of recent developments in computational multiscale mechanics. Both upscaling and concurrent computing methodologies will be addressed for a range of application areas in computational solid and fluid mechanics: Scale transitions in materials, turbulence in fluid-structure interaction problems, multiscale/multilevel optimization, multiscale poromechanics. A Dutch-German research group that consists of qualified and well-known researchers in the field has worked for six years on the topic of computational multiscale mechanics. This text provides a unique opportunity to consolidate and disseminate the knowledge gained in this project. The addition of chapters written by experts outside this working group provides a broad and multifaceted view of this rapidly evolving field.
Book Synopsis A Review of Variational Multiscale Methods for the Simulation of Turbulent Incompressible Flows by : Naveed Ahmed
Download or read book A Review of Variational Multiscale Methods for the Simulation of Turbulent Incompressible Flows written by Naveed Ahmed and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Various realizations of variational multiscale (VMS) methods for simulating turbulent incompressible flows have been proposed in the past fifteen years. All of these realizations obey the basic principles of VMS methods: They are based on the variational formulation of the incompressible Navier-Stokes equations and the scale separation is defined by projections. However, apart from these common basic features, the various VMS methods look quite different. In this review, the derivation of the different VMS methods is presented in some detail and their relation among each other and also to other discretizations is discussed. Another emphasis consists in giving an overview about known results from the numerical analysis of the VMS methods. A few results are presented in detail to highlight the used mathematical tools. Furthermore, the literature presenting numerical studies with the VMS methods is surveyed and the obtained results are summarized.
Book Synopsis Computational Fluid-Structure Interaction by : Yuri Bazilevs
Download or read book Computational Fluid-Structure Interaction written by Yuri Bazilevs and published by John Wiley & Sons. This book was released on 2013-01-25 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Fluid-Structure Interaction: Methods and Applications takes the reader from the fundamentals of computational fluid and solid mechanics to the state-of-the-art in computational FSI methods, special FSI techniques, and solution of real-world problems. Leading experts in the field present the material using a unique approach that combines advanced methods, special techniques, and challenging applications. This book begins with the differential equations governing the fluid and solid mechanics, coupling conditions at the fluid–solid interface, and the basics of the finite element method. It continues with the ALE and space–time FSI methods, spatial discretization and time integration strategies for the coupled FSI equations, solution techniques for the fully-discretized coupled equations, and advanced FSI and space–time methods. It ends with special FSI techniques targeting cardiovascular FSI, parachute FSI, and wind-turbine aerodynamics and FSI. Key features: First book to address the state-of-the-art in computational FSI Combines the fundamentals of computational fluid and solid mechanics, the state-of-the-art in FSI methods, and special FSI techniques targeting challenging classes of real-world problems Covers modern computational mechanics techniques, including stabilized, variational multiscale, and space–time methods, isogeometric analysis, and advanced FSI coupling methods Is in full color, with diagrams illustrating the fundamental concepts and advanced methods and with insightful visualization illustrating the complexities of the problems that can be solved with the FSI methods covered in the book. Authors are award winning, leading global experts in computational FSI, who are known for solving some of the most challenging FSI problems Computational Fluid-Structure Interaction: Methods and Applications is a comprehensive reference for researchers and practicing engineers who would like to advance their existing knowledge on these subjects. It is also an ideal text for graduate and senior-level undergraduate courses in computational fluid mechanics and computational FSI.
Book Synopsis Numerical Methods in Turbulence Simulation by : Robert Moser
Download or read book Numerical Methods in Turbulence Simulation written by Robert Moser and published by Elsevier. This book was released on 2022-11-30 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Numerical Methods in Turbulence Simulation provides detailed specifications of the numerical methods needed to solve important problems in turbulence simulation. Numerical simulation of turbulent fluid flows is challenging because of the range of space and time scales that must be represented. This book provides explanations of the numerical error and stability characteristics of numerical techniques, along with treatments of the additional numerical challenges that arise in large eddy simulations. Chapters are written as tutorials by experts in the field, covering specific both contexts and applications. Three classes of turbulent flow are addressed, including incompressible, compressible and reactive, with a wide range of the best numerical practices covered. A thorough introduction to the numerical methods is provided for those without a background in turbulence, as is everything needed for a thorough understanding of the fundamental equations. The small scales that must be resolved are generally not localized around some distinct small-scale feature, but instead are distributed throughout a volume. These characteristics put particular strain on the numerical methods used to simulate turbulent flows. Includes a detailed review of the numerical approximation issues that impact the simulation of turbulence Provides a range of examples of large eddy simulation techniques Discusses the challenges posed by boundary conditions in turbulence simulation and provides approaches to addressing them
Book Synopsis Development, Verification and Validation of High-order Methods for the Simulation of Turbulence by : Farshad Navah
Download or read book Development, Verification and Validation of High-order Methods for the Simulation of Turbulence written by Farshad Navah and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "This work discusses the development, the verification and the validation of high-order (of accuracy) solvers for the simulation of turbulent fluid flows. In a first part, a methodology for the verification of high-order solvers is proposed which examines the implementation, in a given computer software, of mathematical models that represent the flow dynamics. The method of manufactured solutions is adopted which allows for the exact evaluation of discretization errors and observed orders of accuracy. The latter are compared to the theoretical orders of accuracy for a variety of increasingly complex problems, starting from unbounded (by walls) inviscid flows and gradually reaching the case of realistic turbulent boundary layers, modelled by the Reynolds-averaged Navier-Stokes equations, along with the original and the negative Spalart-Allmaras closure models. Each case serves to illustrate and discuss salient aspects of the proposed methodology.Code verification via manufactured solutions is furthermore distinguished from solution verification and the latter is extended to high-order frameworks by describing the approach for error estimation via extrapolation of high-order solutions which is applied, as an example, to the case of turbulent flow over a flat plate. This exercise enabled the exploration into the question of high-order grid convergence for various output quantities of interest as well as the question of uncertainty analysis. This pointed at the inadequacy of substituting solution verification to proper high-order solver verification, even for a relatively simple problem and an expert set of grids. It is therefore recommended to use the solutions of actual problems for engineering and science applications, only along with estimated numerical uncertainties, especially for lower orders which are more error-prone. In the second part of this work, a compact high-order variational multiscale method for the large-eddy simulation of turbulence is devised and validated. The existing multiscale method is thus expanded from modal frameworks to a large family of compact high-order nodal schemes, represented by the recent flux reconstruction discretization method. The potential of the proposed formulation is then assessed on a Taylor-Green vortex problem and its results are validated against the filtered data from direct numerical simulations. It is thus revealed that proper de-aliasing is mandatory to conserve the quality of high-order large-eddy simulation. Furthermore, reducing the numerical dissipation of Roe's Riemann solver is found to contribute to improving low-Mach flow solutions for variational multiscale methods. Finally, the proposed variational-multiscale formulation resulted in noticeable improvements over the baseline implicit as well as the classical large-eddy simulations." --
Book Synopsis An Assessment of Two Classes of Variational Multiscale Methods for the Simulation of Incompressible Turbulent Flows by : Naveed Ahmed
Download or read book An Assessment of Two Classes of Variational Multiscale Methods for the Simulation of Incompressible Turbulent Flows written by Naveed Ahmed and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Encyclopedia of Computational Mechanics by : Erwin Stein
Download or read book Encyclopedia of Computational Mechanics written by Erwin Stein and published by . This book was released on 2004 with total page 870 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Encyclopedia of Computational Mechanics provides a comprehensive collection of knowledge about the theory and practice of computational mechanics.
Book Synopsis IDIHOM: Industrialization of High-Order Methods - A Top-Down Approach by : Norbert Kroll
Download or read book IDIHOM: Industrialization of High-Order Methods - A Top-Down Approach written by Norbert Kroll and published by Springer. This book was released on 2015-01-02 with total page 683 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book describes the main findings of the EU-funded project IDIHOM (Industrialization of High-Order Methods – A Top-Down Approach). The goal of this project was the improvement, utilization and demonstration of innovative higher-order simulation capabilities for large-scale aerodynamic application challenges in the aircraft industry. The IDIHOM consortium consisted of 21 organizations, including aircraft manufacturers, software vendors, as well as the major European research establishments and several universities, all of them with proven expertise in the field of computational fluid dynamics. After a general introduction to the project, the book reports on new approaches for curved boundary-grid generation, high-order solution methods and visualization techniques. It summarizes the achievements, weaknesses and perspectives of the new simulation capabilities developed by the project partners for various industrial applications, and includes internal- and external-aerodynamic as well as multidisciplinary test cases.
Book Synopsis The Role of Continuity in Residual-Based Variational Multiscale Modeling of Turbulence by :
Download or read book The Role of Continuity in Residual-Based Variational Multiscale Modeling of Turbulence written by and published by . This book was released on 2007 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper examines the role of continuity of the basis in the computation of turbulent flows. We compare standard finite elements and NURBS (non-uniform rational B-splines) discretizations that are employed in Isogeometric Analysis. We make use of quadratic discretizations that are C0-continuous across element boundaries in standard finite elements, and C1-continuous in the case of NURBS. The variational multiscale residual-based method is employed as a turbulence modeling technique. We find that C1-continuous discretizations outperform their C0-continuous counterparts on a per-degree-of- freedom basis. We also find that the effect of continuity is greater for higher Reynolds number flows.
Book Synopsis Variational Multiscale Modeling for Turbulence Control by : Srinivas Ramakrishnan
Download or read book Variational Multiscale Modeling for Turbulence Control written by Srinivas Ramakrishnan and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Multiscale And Multiresolution Approaches In Turbulence - Les, Des And Hybrid Rans/les Methods: Applications And Guidelines (2nd Edition) by : Pierre Sagaut
Download or read book Multiscale And Multiresolution Approaches In Turbulence - Les, Des And Hybrid Rans/les Methods: Applications And Guidelines (2nd Edition) written by Pierre Sagaut and published by World Scientific. This book was released on 2013-03-25 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book aims to provide the reader with an updated general presentation of multiscale/multiresolution approaches in turbulent flow simulations. All modern approaches (LES, hybrid RANS/LES, DES, SAS) are discussed and recast in a global comprehensive framework. Both theoretical features and practical implementation details are addressed. Some full scale applications are described, to provide the reader with relevant guidelines to facilitate a future use of these methods./a
