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We propose and analyze a discretization scheme that combines the discontinuous Petrov-Galerkin and finite element methods. The underlying model problem is of general diffusion-advection-reaction type on bounded domains, with decomposition…

Numerical Analysis · Mathematics 2017-04-26 Thomas Führer , Norbert Heuer , Michael Karkulik , Rodolfo Rodríguez

We introduce a new class of fractional backward orthogonal functions designed for the spectral approximation of weakly singular adjoint Volterra integral equations. These basis functions generate an approximation space that naturally…

Numerical Analysis · Mathematics 2026-05-29 Mahmoud A. Zaky

In this paper, authors shall introduce a finite element method by using a weakly defined gradient operator over discontinuous functions with heterogeneous properties. The use of weak gradients and their approximations results in a new…

Numerical Analysis · Mathematics 2012-11-14 Junping Wang , Xiu Ye

We present a new stability and error analysis of fully discrete approximation schemes for the transient Stokes equation. For the spatial discretization, we consider a wide class of Galerkin finite element methods which includes both inf-sup…

Numerical Analysis · Mathematics 2023-12-12 Alessandro Contri , Balázs Kovács , André Massing

Adjoint methods have gained popularity in recent years for driving adaptation procedures which aim to reduce error in solution functionals. While adjoint methods have been proven effective for functional-based adaptation, the practical…

Fluid Dynamics · Physics 2015-11-09 William C. Tyson , Christopher J. Roy

The aim of this work is to show an abstract framework to analyze the numerical approximation for a family of linear degenerate parabolic mixed equations by using a finite element method in space and a Backward-Euler scheme in time. We…

Numerical Analysis · Mathematics 2020-09-08 Ramiro Acevedo , Christian Gómez , Bibiana López-Rodríguez

In this paper we demonstrate a new technique for deriving discrete adjoint and tangent linear models of finite element models. The technique is significantly more efficient and automatic than standard algorithmic differentiation techniques.…

Mathematical Software · Computer Science 2013-10-17 Patrick E. Farrell , David A. Ham , Simon F. Funke , Marie E. Rognes

This paper develops and analyzes a class of semi-discrete and fully discrete weak Galerkin finite element methods for unsteady incompressible convective Brinkman-Forchheimer equations. For the spatial discretization, the methods adopt the…

Numerical Analysis · Mathematics 2024-10-30 Xiaojuan Wang , Jihong Xiao , Xiaoping Xie , Shiquan Zhang

The backward differentiation formula (BDF) is a useful family of implicit methods for the numerical integration of stiff differential equations. It is well noticed that the stability and convergence of the $A$-stable BDF1 and BDF2 schemes…

Numerical Analysis · Mathematics 2021-02-10 Honglin Liao , Tao Tang , Tao Zhou

In this paper we consider fully discrete approximations with inf-sup stable mixed finite element methods in space to approximate the Navier-Stokes equations. A continuous downscaling data assimilation algorithm is analyzed in which…

Numerical Analysis · Mathematics 2019-04-15 Bosco García-Archilla , Julia Novo

The adjoint method, recently introduced by Evans, is used to study obstacle problems, weakly coupled systems, cell problems for weakly coupled systems of Hamilton-Jacobi equations, and weakly coupled systems of obstacle type. In particular,…

Analysis of PDEs · Mathematics 2013-03-13 Filippo Cagnetti , Diogo Gomes , Hung Tran

This article introduces and analyzes a weak Galerkin mixed finite element method for solving the biharmonic equation. The weak Galerkin method, first introduced by two of the authors (J. Wang and X. Ye) in an earlier publication for second…

Numerical Analysis · Mathematics 2012-12-05 Lin Mu , Junping Wang , Yanqiu Wang , Xiu Ye

The novel idea of weak Galerkin (WG) finite element methods is on the use of weak functions and their weak derivatives defined as distributions. Weak functions and weak derivatives can be approximated by polynomials with various degrees.…

Numerical Analysis · Mathematics 2013-04-25 Lin Mu , Junping Wang , Xiu Ye

We begin by addressing the time-domain full-waveform inversion using the adjoint method. Next, we derive the scaled boundary semi-weak form of the scalar wave equation in heterogeneous media through the Galerkin method. Unlike conventional…

Numerical Analysis · Mathematics 2025-01-14 Alireza Daneshyar , Stefan Kollmannsberger

In this work, the authors introduce a generalized weak Galerkin (gWG) finite element method for the time-dependent Oseen equation. The generalized weak Galerkin method is based on a new framework for approximating the gradient operator.…

Numerical Analysis · Mathematics 2022-09-14 Wenya Qi , Padmanabhan Seshaiyer , Junping Wang

This paper proposes and analyzes an implicit-explicit BDF-Galerkin scheme of second order for the time-dependent nonlinear thermistor problem. For this, we combine the second-order backward differentiation formula with special extrapolation…

Numerical Analysis · Mathematics 2026-05-29 R. Altmann , A. Moradi

This paper presents a primal-dual weak Galerkin (PD-WG) finite element method for a class of second order elliptic equations of Fokker-Planck type. The method is based on a variational form where all the derivatives are applied to the test…

Numerical Analysis · Mathematics 2017-04-20 Chunmei Wang , Junping Wang

We consider a model convection-diffusion problem and present useful connections between the finite differences and finite element discretization methods. We introduce a general upwinding Petrov-Galerkin discretization based on bubble…

Numerical Analysis · Mathematics 2024-02-07 Constantin Bacuta , Cristina Bacuta

In this work we address the analysis of the stationary generalized Burgers-Huxley equation (a nonlinear elliptic problem with anomalous advection) and propose conforming, nonconforming and discontinuous Galerkin finite element methods for…

Numerical Analysis · Mathematics 2021-01-13 Arbaz Khan , Manil T Mohan , Ricardo Ruiz-Baier

In this paper, we propose a new numerical scheme for the coupled Stokes-Darcy model with Beavers-Joseph-Saffman interface condition. We use the weak Galerkin method to discretize the Stokes equation and the mixed finite element method to…

Numerical Analysis · Mathematics 2021-03-02 Hui Peng , Qilong Zhai , Ran Zhang , Shangyou Zhang
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