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Problems with sign-changing coefficients occur, for instance, in the study of transmission problems with metamaterials. In this work, we present and analyze a generalized finite element method in the spirit of the Localized Orthogonal…

Numerical Analysis · Mathematics 2020-08-28 Théophile Chaumont-Frelet , Barbara Verfürth

Let us consider the singularly perturbed model problem $Lu:=-\varepsilon\Delta u-bu_x+c u =f$ with homogeneous Dirichlet boundary conditions on $\Gamma=\partial\Omega$ $u|_\Gamma =0$ on the unit-square $\Omega=(0,1)^2$. Assuming that $b>0$…

Numerical Analysis · Mathematics 2014-03-04 Sebastian Franz

In this paper we formulate and analyse adaptive (space-time) least-squares finite element methods for the solution of convection-diffusion equations. The convective derivative $\mathbf{v} \cdot \nabla u$ is considered as part of the total…

Numerical Analysis · Mathematics 2025-09-16 Christian Köthe , Olaf Steinbach

We formulate a stabilized quasi-optimal Petrov-Galerkin method for singularly perturbed convection-diffusion problems based on the variational multiscale method. The stabilization is of Petrov-Galerkin type with a standard finite element…

Numerical Analysis · Mathematics 2016-06-16 Guanglian Li , Daniel Peterseim , Mira Schedensack

The properties of liquid crystals can be modelled using an order parameter which describes the variability of the local orientation of rod-like molecules. Defects in the director field can arise due to external factors such as applied…

Numerical Analysis · Mathematics 2019-10-08 Craig S. MacDonald , John A. Mackenzie , Alison Ramage

The objective of this contribution is to develop a convergence analysis for SUPG-stabilized Virtual Element Methods in diffusion-convection problems that is robust also in the convection dominated regime. For the original method introduced…

Numerical Analysis · Mathematics 2020-12-03 L. Beirão da Veiga , F. Dassi , C. Lovadina , G. Vacca

A simple but successful strategy for building a discrete diffusion operator in finite volume schemes of industrial use is to correct the standard two-point flux approximation with a term accounting for the local mesh non-orthogonality.…

Numerical Analysis · Mathematics 2018-06-26 L. Bonaventura , A. Della Rocca

A new field of numerical astrophysics is introduced which addresses the solution of large, multidimensional structural or slowly-evolving problems (rotating stars, interacting binaries, thick advective accretion disks, four dimensional…

Astrophysics · Physics 2009-10-30 David L. Meier

This work is aimed at the derivation of reliable and efficient a posteriori error estimates for convection-dominated diffusion problems motivated by a linear Fokker-Planck problem appearing in computational neuroscience. We obtain…

Numerical Analysis · Computer Science 2018-05-16 Svetlana Matculevich , Monika Wolfmayr

In this paper, a semi-discrete spatial finite volume (FV) method is proposed and analyzed for approximating solutions of anomalous subdiffusion equations involving a temporal fractional derivative of order $\alpha \in (0,1)$ in a…

Numerical Analysis · Mathematics 2015-10-27 Samir Karaa , Kassem Mustapha , Amiya K. Pani

We present a numerical analysis of a higher order unfitted space-time Finite Element method applied to a convection-diffusion model problem posed on a moving bulk domain. The method uses isoparametric space-time mappings for the geometry…

Numerical Analysis · Mathematics 2025-12-11 Fabian Heimann , Christoph Lehrenfeld , Janosch Preuß

Multilayer diffusion problems have found significant important that they arise in many medical, environmental and industrial applications of heat and mass transfer. In this article, we study the solvability of one-dimensional nonhomogeneous…

Analysis of PDEs · Mathematics 2021-09-15 Mohamed Akel , Hillal M. Elshehabey , Ragaa Ahmed

Mesh adaptivity is a useful tool for efficient solution to partial differential equations in very complex geometries. In the present paper we discuss the use of polygonal mesh refinement in order to tackle two common issues: first,…

Numerical Analysis · Mathematics 2021-12-21 Stefano Berrone , Alessandro D'Auria

The instantaneous two-dimensional wall shear rate is assessed through an inverse problem using mass transfer data from a three-segment electrodiffusion probe. The method is validated numerically in complex flow conditions involving (i) high…

Fluid Dynamics · Physics 2018-12-19 Marc-Étienne Lamarche-Gagnon , Jérôme Vétel

This article presents a new finite element method for convection-diffusion equations by enhancing the continuous finite element space with a flux space for flux approximations that preserve the important mass conservation locally on each…

Numerical Analysis · Mathematics 2017-10-24 Yujie Liu , Junping Wang , Qingsong Zou

Diffusion-driven patterns appear on curved surfaces in many settings, initiated by unstable modes of an underlying Laplacian operator. On a flat surface or perfect sphere, the patterns are degenerate, reflecting translational/rotational…

Soft Condensed Matter · Physics 2025-09-09 John R. Frank , Jemal Guven , Mehran Kardar , Leyna Shackleton

The fast diffusion equation is analyzed on a bounded domain with Dirichlet boundary conditions, for which solutions are known to extinct in finite time. We construct invariant manifolds that provide a finite-dimensional approximation near…

Analysis of PDEs · Mathematics 2024-04-02 Beomjun Choi , Christian Seis

The aim of this paper is to develop a numerical scheme to approximate evolving interface problems for parabolic equations based on the abstract evolving finite element framework proposed in (C M Elliott, T Ranner, IMA J Num Anal, 41:3,…

Numerical Analysis · Mathematics 2026-05-15 C. M. Elliott , T. Ranner , P. Stepanov

A fractional diffusion equation with advection term is rigorously derived from a kinetic transport model with a linear turning operator, featuring a fat-tailed equilibrium distribution and a small directional bias due to a given vector…

Analysis of PDEs · Mathematics 2015-10-19 Pedro Aceves-Sanchez , Christian Schmeiser

Diffusion models have demonstrated exceptional performances in various fields of generative modeling, but suffer from slow sampling speed due to their iterative nature. While this issue is being addressed in continuous domains, discrete…

Machine Learning · Computer Science 2025-05-12 Satoshi Hayakawa , Yuhta Takida , Masaaki Imaizumi , Hiromi Wakaki , Yuki Mitsufuji