Download or read book Oscillation Absorption Finite Element Methods for Convection diffusion Problems written by William J. Layton and published by . This book was released on 1993 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Finite Element Formulation for the Numerical Solution of the Convection diffusion Equation written by Ramon Codina and published by . This book was released on 1993 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite Element Methods for Convection Dominated Flows written by Thomas J. R. Hughes and published by . This book was released on 1979 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stabilized Finite Element Methods for Convection diffusion reaction Helmholtz and Stokes Problems written by Prashanth Nadukandi and published by . This book was released on 2012 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Moving Mesh Finite Element Method for Time Dependent Convection Diffusion Problems written by Matthew Maxwell McCoy and published by . This book was released on 2021 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The moving mesh finite element method (MM-FEM) has been a significant force in numerically approximating solutions to differential equations that otherwise exhibit spurious, artificial oscillations. This is especially true for singularly perturbed convection-diffusion problems. In the presence of vanishing molecular diffusivity, MM- FEM may not suffice. The numerical method may exhibit under-diffusive properties and other methods need to be integrated into the classic Galerkin formulation. We implement the so-called streamline upwind Petrov-Galerkin method into the adaptive moving mesh method. In particular, we investigate the computation of so-called enhanced diffusivity for spatiotemporal periodic turbulent flows. We look at the case of Brownian tracer particles, i.e. negligible inertial effects. These types of passive advection-diffusion models are used in atmospheric models with turbulent diffusion, so-called Benard-advection cells, and porous materials, along with many other areas of science and engineering. As molecular diffusivity decreases, interior and boundary layers propagate along the streamlines. Once spurious oscillations are present, they too will propagate along the streamlines. Thus, specialized numerical methods are needed in order to resolve these areas of the domain where large gradients are present. The discrete maximum principle is also investigated for general anisotropic time dependent convection-diffusion equations. We obtain lower and upper bounds for time steps as well as obtain conditions on the mass and stiffness matrices resulting from the SUPG formulation. Our approach depends on two meshes and taking into consideration two diffusion matrices and applying metric intersection.
Download or read book Moving Space time Finite Element Methods for Convection diffusion Problems written by Rafael Brigham Neves Ferreira Santos and published by . This book was released on 1991 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book SIAM Journal on Scientific Computing written by and published by . This book was released on 2008 with total page 1402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stabilized Finite Element Methods for Convection diffusion Problems written by Amal Khalid Al-Shanfari and published by . This book was released on 2012 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite element methods for convection diffusion problems written by Owe Axelsson and published by . This book was released on 1987 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Finite Element Method for Convection diffusion Problems written by Chalmers University of Technology. Dept. of Computer Sciences and published by . This book was released on 1982 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite Element Analysis of a Convection diffusion Equation written by José Avila and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Finite Element Methods with Multigrid for the Convection diffusion Equation written by Darren Furnival and published by . This book was released on 2001 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Numerical Oscillations and Higher degree Finite Elements for Convection diffusion written by Tayfun Yener Umucu and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Discontinuous Petrov Galerkin Methods with Optimal Test Spaces for Convection Dominated Convection diffusion Equations written by Dirk Broersen and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this thesis, Discontinuous Petrov-Galerkin (DPG) finite element methods are developed for convection-diffusion equations. In particular, this thesis focuses on the use of optimal test spaces. A convection-diffusion equation is a singularly perturbed problem. That is, the nature of the problem changes when the diffusion term vanishes, which makes it challenging to solve numerically for small diffusion values, i.e. when convection dominates. Standard finite element methods give very unsatisfactory results, producing approximations that exhibit spurious oscillations and other nonphysical behavior. Recently, a class of finite element methods has been developed, in which optimal test spaces are used. These spaces guarantee that one gets the best approximation from the trial space in which the solution is sought. The methods are examples of least-squares methods, with the special property that one can choose the norm in which the residual is minimized. This freedom of choice allows us to control the norm in which the best approximation is obtained. The new approach in this thesis is that the variational formulation associated with the convection-diffusion problem also gives a well-posed variational formulation of the limit convection problem if the diffusion term vanishes. This is necessary in order to retain stability, and to make sure that the computational cost does not grow, when the diffusion term decreases. Special attention is paid to the transport problem which, besides being the limit problem for vanishing diffusion, also has other applications. A new method is introduced that outperforms existing methods in convergence rates, but also in reducing the smearing of discontinuities of solutions. The theory developed in this thesis is illustrated by various numerical results."--Samenvatting auteur.
Download or read book Numerical Implementation of a Mixed Finite Element Formulation for Convection diffusion Problems written by Ivan Padilla Montero and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This document aims to the numerical solution of convection-diffusion problems in a fluid dynamics context by means of the Finite Element Method (FEM). It describes the classical finite element solution of convection-diffusion problems and presents the implementation and validation of a new formulation for improving the accuracy of the standard approach. On first place, the importance and need of numerical convection-diffusion models for Computational Fluid Dynamics (CFD) is emphasized, highlighting the similarities between the convection-diffusion equation and the governing equations of fluid dynamics for incompressible flow. The basic aspects of the finite element method needed for the standard solution of general convection-diffusion problems are then explained and applied to the steady state case. These include the weak formulation of the initial boundary value problem for the convection-diffusion equation and the posterior finite element spatial discretization of the weak form based on the Galerkin method. After their application to the steady transport equation a simple numerical test is performed to show that the standard Galerkin formulation is not stable in convection-dominated situations, and the need for stabilization is justified. Attention is then focused on the analysis of the truncation error provided by the Galerkin formulation, leading to the derivation of a classical stabilization technique based on the addition of artificial diffusion along the flow direction, the so-called streamline-upwind (SU) schemes. Next, a more general and modern stabilization approach known as the Sub-Grid-Scale (SGS) method is described, showing that SU schemes are a particular case of it. Taking into account all the concepts explained, a new mixed finite element formulation for convection-diffusion problems is presented. It has been proposed by Dr. Riccardo Rossi, a researcher from the International Center for Numerical Methods in Engineering (CIMNE), and consists on extending the original convection-diffusion equation to a system in mixed form in which both the unknown variable and its gradient are computed simultaneously, leading to an increase in the convergence rate of the solution. The formulation, which had not been tested before, is then implemented and validated by means of a multiphysics finite element software called \texttt{Kratos}. Eventually, the obtained results are analyzed, showing the improved performance of the mixed formulation in pure diffusion problems.
Download or read book An Adaptive Finite Element Method for Convection Diffusion Problems written by William Gerard Szymczak and published by . This book was released on 1982 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Report written by and published by . This book was released on 1993 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
