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The numerical approximation of an inverse problem subject to the convection--diffusion equation when diffusion dominates is studied. We derive Carleman estimates that are on a form suitable for use in numerical analysis and with explicit…

Numerical Analysis · Mathematics 2020-06-25 Erik Burman , Mihai Nechita , Lauri Oksanen

In this article a simplified weak Galerkin finite element method is developed for the Dirichlet boundary value problem of convection-diffusion-reaction equations. The simplified weak Galerkin method utilizes only the degrees of freedom on…

Numerical Analysis · Mathematics 2018-08-29 Yujie Liu , Junping Wang

The increasing application of cardiorespiratory simulations for diagnosis and surgical planning necessitates the development of computational methods significantly faster than the current technology. To achieve this objective, we leverage…

Numerical Analysis · Mathematics 2024-03-21 Mahdi Esmaily , Dongjie Jia

Diffusive representations of fractional derivatives have proven to be useful tools in the construction of fast and memory efficient numerical methods for solving fractional differential equations. A common challenge in many of the known…

Numerical Analysis · Mathematics 2022-04-11 Kai Diethelm

We present a finite element discretization of a non-linear diffusion equation used in the field of critical phenomena and, more recently, in the context of Dynamic Density Functional Theory. The discretized equation preserves the structure…

Statistical Mechanics · Physics 2015-06-23 J. A. de la Torre , Pep Español , Aleksandar Donev

Adaptive finite elements are the method of choice for accurate simulations of optical components. However as shown recently by Bienstman et al. many finite element mode solvers fail to compute the propagation constant's imaginary part of a…

Optics · Physics 2009-05-28 L. Zschiedrich , S. Burger , J. Pomplun , F. Schmidt

The finite element method (FEM) is applied to obtain numerical solutions to a recently derived nonlinear equation for the shallow water wave problem. A weak formulation and the Petrov-Galerkin method are used. It is shown that the FEM gives…

Fluid Dynamics · Physics 2016-09-20 Anna Karczewska , Piotr Rozmej , Maciej Szczeciński , Bartosz Boguniewicz

In this paper, we develop a multiphysics finite element method for solving the quasi-static thermo-poroelasticity model with nonlinear permeability. The model involves multiple physical processes such as deformation, pressure, diffusion and…

Numerical Analysis · Mathematics 2026-02-24 Zhihao Ge , Wenshuai Hu

We present a Heterogeneous Multiscale Method for the Landau-Lifshitz equation with a highly oscillatory diffusion coefficient, a simple model for a ferromagnetic composite. A finite element macro scheme is combined with a finite difference…

Numerical Analysis · Mathematics 2021-11-23 Lena Leitenmaier , Murtazo Nazarov

In this article, the piecewise-linear finite element method (FEM) is applied to approximate the solution of time-fractional diffusion equations on bounded convex domains. Standard energy arguments do not provide satisfactory results for…

Numerical Analysis · Mathematics 2018-11-06 Samir Karaa , Kassem Mustapha , Amiya K. Pani

Error estimates are proved for finite element approximations to the solution of second-order hyperbolic partial differential equations with coefficients varying in both space and time. Optimal rates of convergence in the energy norm are…

Numerical Analysis · Mathematics 2026-03-17 Oussama Al Jarroudi , Marcus J. Grote

In this work, a complete error analysis is presented for fully discrete solutions of the subdiffusion equation with a time-dependent diffusion coefficient, obtained by the Galerkin finite element method with conforming piecewise linear…

Numerical Analysis · Mathematics 2018-09-24 Bangti Jin , Buyang Li , Zhi Zhou

An initial-boundary value problem for the time-fractional diffusion equation is discretized in space using continuous piecewise-linear finite elements on a polygonal domain with a re-entrant corner. Known error bounds for the case of a…

Numerical Analysis · Mathematics 2017-12-21 Kim Ngan Le , William McLean , Bishnu Lamichhane

Conventional X-ray methods use incoming plane waves and result in discrete diffraction patterns when scattered at crystals. Here we find, by a systematic method, incoming waveforms which exhibit discrete diffraction patterns when scattered…

Optics · Physics 2015-06-16 Gero Friesecke , Richard D. James , Dominik Jüstel

A new modified Galerkin / Finite Element Method is proposed for the numerical solution of the fully nonlinear shallow water wave equations. The new numerical method allows the use of low-order Lagrange finite element spaces, despite the…

Numerical Analysis · Mathematics 2016-09-21 Dimitrios Mitsotakis , Costas Synolakis , Mark Mcguinness

A finite element-based modal formulation of diffraction of a plane wave by an absorbing photonic crystal slab of arbitrary geometry is developed for photovoltaic applications. The semi-analytic approach allows efficient and accurate…

We present and analyze a space-time Petrov-Galerkin finite element method for a time-fractional diffusion equation involving a Riemann-Liouville fractional derivative of order $\alpha\in(0,1)$ in time and zero initial data. We derive a…

Numerical Analysis · Mathematics 2017-07-26 Beiping Duan , Bangti Jin , Raytcho Lazarov , Joseph Pasciak , Zhi Zhou

Dark-Field X-ray Microscopy (DFXM) is a diffraction-based synchrotron imaging techique capable of imaging defects in the bulk of extended crystalline samples. We present numerical simulations of image-formation in such a microscope using…

Materials Science · Physics 2022-02-24 Mads Carlsen , Carsten Detlefs , Can Yildirim , Trygve Ræder , Hugh Simons

We study the numerical approximation of advection-diffusion equations with highly oscillatory coefficients and possibly dominant advection terms by means of the Multiscale Finite Element Method. The latter method is a now classical, finite…

Numerical Analysis · Mathematics 2024-11-12 Rutger A. Biezemans , Claude Le Bris , Frédéric Legoll , Alexei Lozinski

In this paper, we develop a modified nonlinear dynamic diffusion (DD) finite element method for convection-diffusion-reaction equations. This method is free of stabilization parameters and is capable of precluding spurious oscillations. We…

Numerical Analysis · Mathematics 2025-03-11 Shaohong Du , Qianqian Hou , Xiaoping Xie