# Multiscale Finite Element MethodsMultiscale Finite Element Methods The book addresses mathematical and numerical issues in multiscale finite element methods and connects them to real-world applications. Narrative introduction provides a key to the book's organization and its scope.

Author: Yalchin Efendiev

Publisher: Springer Science & Business Media

ISBN: 9780387094960

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Page: 234

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The aim of this monograph is to describe the main concepts and recent - vances in multiscale ?nite element methods. This monograph is intended for thebroaderaudienceincludingengineers,appliedscientists,andforthosewho are interested in multiscale simulations. The book is intended for graduate students in applied mathematics and those interested in multiscale compu- tions. It combines a practical introduction, numerical results, and analysis of multiscale ?nite element methods. Due to the page limitation, the material has been condensed. Each chapter of the book starts with an introduction and description of the proposed methods and motivating examples. Some new techniques are introduced using formal arguments that are justi?ed later in the last chapter. Numerical examples demonstrating the signi?cance of the proposed methods are presented in each chapter following the description of the methods. In the last chapter, we analyze a few representative cases with the objective of demonstrating the main error sources and the convergence of the proposed methods. A brief outline of the book is as follows. The ?rst chapter gives a general introductiontomultiscalemethodsandanoutlineofeachchapter.Thesecond chapter discusses the main idea of the multiscale ?nite element method and its extensions. This chapter also gives an overview of multiscale ?nite element methods and other related methods. The third chapter discusses the ext- sion of multiscale ?nite element methods to nonlinear problems. The fourth chapter focuses on multiscale methods that use limited global information.

# Multiscale Finite Element Methods For Second Order Elliptic BVPsMultiscale Finite Element Methods For Second Order Elliptic BVPs In this book the convergence of the multiscale finite element method (MsFEM) for second order elliptic equations with oscillating coefficient in two space dimension is studied.

Author: Md Selim Akhtar

ISBN: 3843374171

Category:

Page: 80

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In this book the convergence of the multiscale finite element method (MsFEM) for second order elliptic equations with oscillating coefficient in two space dimension is studied. Such equations often arise in composite materials and flows in porous media. The main purpose is to understand the theoretical background of this method and its convergence analysis. The oscillating coefficient is assumed to be of two scales and is periodic in the large scale. The MsFEM is capable of correctly capturing the large scale components of the solution on a coarse grid without accurately resolving all the small scale features in the solution. This is accomplished by incorporating the local microstructure of the differential operator into the finite element base functions. As a consequence, the base functions are adapted to the local properties of the differential operator.

# Multiscale Finite Element MethodsMultiscale Finite Element Methods This text on the main concepts and recent advances in multiscale finite element methods is written for a broad audience.

Author: Thomas Hou

Publisher: Springer

ISBN: UCAL:B4423391

Category:

Page: 337

View: 562

This text on the main concepts and recent advances in multiscale finite element methods is written for a broad audience. Each chapter contains a simple introduction, a description of proposed methods, and numerical examples of those methods.

# Generalization of Mixed Multiscale Finite Element Methods with ApplicationsGeneralization of Mixed Multiscale Finite Element Methods with Applications Application of the algorithm in two-phase flow simulations are demonstrated. For linear elasticity, the algorithm is subtly modified due to the symmetry requirement of the stress tensor. The latter enrichment approach is based on rAMGe.

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ISBN: OCLC:957097096

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Page: 167

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Many science and engineering problems exhibit scale disparity and high contrast. The small scale features cannot be omitted in the physical models because they can affect the macroscopic behavior of the problems. However, resolving all the scales in these problems can be prohibitively expensive. As a consequence, some types of model reduction techniques are required to design efficient solution algorithms. For practical purpose, we are interested in mixed finite element problems as they produce solutions with certain conservative properties. Existing multiscale methods for such problems include the mixed multiscale finite element methods. We show that for complicated problems, the mixed multiscale finite element methods may not be able to produce reliable approximations. This motivates the need of enrichment for coarse spaces. Two enrichment approaches are proposed, one is based on generalized multiscale finte element metthods (GMsFEM), while the other is based on spectral element-based algebraic multigrid (rAMGe). The former one, which is called mixed GMsFEM, is developed for both Darcy's flow and linear elasticity. Application of the algorithm in two-phase flow simulations are demonstrated. For linear elasticity, the algorithm is subtly modified due to the symmetry requirement of the stress tensor. The latter enrichment approach is based on rAMGe. The algorithm differs from GMsFEM in that both of the velocity and pressure spaces are coarsened. Due the multigrid nature of the algorithm, recursive application is available, which results in an efficient multilevel construction of the coarse spaces. Stability, convergence analysis, and exhaustive numerical experiments are carried out to validate the proposed enrichment approaches. iii.

# Numerical Analysis of Multiscale ProblemsNumerical Analysis of Multiscale Problems Y. Efendiev, V. Ginting, T. Hou, and R. Ewing, Accurate multiscale finite element methods for two-phase flow simulations, J. Comp. Physics, 220 (1), 155–174, 2006. Y. Efendiev and T. Hou, Multiscale finite element methods.

Author: Ivan G. Graham

Publisher: Springer Science & Business Media

ISBN: 9783642220616

Category:

Page: 374

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The 91st London Mathematical Society Durham Symposium took place from July 5th to 15th 2010, with more than 100 international participants attending. The Symposium focused on Numerical Analysis of Multiscale Problems and this book contains 10 invited articles from some of the meeting's key speakers, covering a range of topics of contemporary interest in this area. Articles cover the analysis of forward and inverse PDE problems in heterogeneous media, high-frequency wave propagation, atomistic-continuum modeling and high-dimensional problems arising in modeling uncertainty. Novel upscaling and preconditioning techniques, as well as applications to turbulent multi-phase flow, and to problems of current interest in materials science are all addressed. As such this book presents the current state-of-the-art in the numerical analysis of multiscale problems and will be of interest to both practitioners and mathematicians working in those fields.

# Finite Element Modeling of Multiscale Transport PhenomenaFinite Element Modeling of Multiscale Transport Phenomena Franca, L.P. and Farhat, C., Bubble functions prompt unusual stabilized finite element methods, Comput. Meth. Appl. Mech. Eng., 1995; 123; 299–308. Fried, I., Finite-element analysis of time-dependent phenomena, AIAA J, 1969; 7; ...

Author: Vahid Nassehi

Publisher: World Scientific

ISBN: 9781848164291

Category:

Page: 250

View: 685

Complex multiscale systems such as combined free or porous flow regimes and transport processes governed by combined diffusion, convection and reaction mechanisms, which cannot be readily modeled using traditional methods, can be solved by multiscale or stabilized finite element schemes. Due to the importance of the described multiscale processes in applications such as separation processes, reaction engineering and environmental systems analysis, a sound knowledge of such methods is essential for many researchers and design engineers who wish to develop reliable solutions for industrially relevant problems. The main scope of this book is to provide an authoritative description of recent developments in the field of finite element analysis, with a particular emphasis on the multiscale finite element modeling of transport phenomena and flow problem.

# Multiscale Methods in Science and EngineeringMultiscale Methods in Science and Engineering J. Aarnes, On the use of a mixed multiscale finite element method for greater flexibility and increased speed or improved accuracy in reservoir simulation, Multiscale Model. Simul., 2, 421–439, (2004). 2. J. Aarnes, Efficient domain ...

Author: Björn Engquist

Publisher: Springer Science & Business Media

ISBN: 9783540264446

Category:

Page: 289

View: 570

Multiscale problems naturally pose severe challenges for computational science and engineering. The smaller scales must be well resolved over the range of the larger scales. Challenging multiscale problems are very common and are found in e.g. materials science, fluid mechanics, electrical and mechanical engineering. Homogenization, subgrid modelling, heterogeneous multiscale methods, multigrid, multipole, and adaptive algorithms are examples of methods to tackle these problems. This volume is an overview of current mathematical and computational methods for problems with multiple scales with applications in chemistry, physics and engineering.

# Generalized Multiscale Finite element Method GMsFEM for Elastic Wave Propagation in Heterogeneous Anisotropic MediaGeneralized Multiscale Finite element Method GMsFEM for Elastic Wave Propagation in Heterogeneous Anisotropic Media We propose a Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both the boundaries and interior of a ...

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Publisher:

ISBN: OCLC:951620406

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Page: 28

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It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling methods, such as finite-difference method and finite-element method, becomes prohibitively expensive when applied to very large models. We propose a Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both the boundaries and interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale medium property variations, and allows us to greatly reduce the degrees of freedom that are required to implement the modeling compared with conventional finite-element method for wave equation, while restricting the error to low values. We formulate the continuous Galerkin and discontinuous Galerkin formulation of the multiscale method, both of which have pros and cons. Applications of the multiscale method to three heterogeneous models show that our multiscale method can effectively model the elastic wave propagation in anisotropic media with a significant reduction in the degrees of freedom in the modeling system.