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We consider the numerical approximation of the ill-posed data assimilation problem for stationary convection-diffusion equations and extend our previous analysis in [Numer. Math. 144, 451--477, 2020] to the convection-dominated regime.…

Numerical Analysis · Mathematics 2022-02-22 Erik Burman , Mihai Nechita , Lauri Oksanen

Convection-diffusion equations arise in a variety of applications such as particle transport, electromagnetics, and magnetohydrodynamics. Simulation of the convection-dominated regime for these problems, even with high-fidelity techniques,…

Numerical Analysis · Mathematics 2023-05-24 James H. Adler , Casey Cavanaugh , Xiaozhe Hu , Andy Huang , Nathaniel Trask

In this work, we introduce a new difference equation which is discrete analogue of Diffusion differential equation and analyze some essential spectral properties, Diffusion difference operator is self-adjoint, eigenvalues of this problem…

Spectral Theory · Mathematics 2017-05-03 Erdal Bas , Ramazan Ozarslan

In this paper, we present a numerical verification method of solutions for nonlinear parabolic initial boundary value problems. Decomposing the problem into a nonlinear part and an initial value part, we apply Nakao's projection method,…

Numerical Analysis · Mathematics 2020-01-16 Kouji Hashimoto , Takehiko Kinoshita , Mitsuhiro T. Nakao

We study a second-order parabolic equation with divergence form elliptic operator, having piecewise constant diffusion coefficients with two points of discontinuity. Such partial differential equations appear in the modelization of…

Probability · Mathematics 2013-12-31 Zhen-Qing Chen , Mounir Zili

A three-point monotone difference scheme is proposed for solving a one-dimensional non-stationary convection-diffusion-reaction equation with variable coefficients. The scheme is based on a parabolic spline and allows to linearly reproduce…

Numerical Analysis · Computer Science 2017-12-25 O. Stelia , L. Potapenko , I. Sirenko

In this paper we consider a problem of initial data identification from the final time observation for homogeneous parabolic problems. It is well-known that such problems are exponentially ill-posed due to the strong smoothing property of…

Optimization and Control · Mathematics 2019-05-06 Dmitriy Leykekhman , Boris Vexler , Daniel Walter

For a one-dimensional wave equation, we consider a mixed problem in a curvilinear half-strip. The initial conditions have a first-kind discontinuity at one point. The mixed problem models the problem of a longitudinal impact on a finite…

Analysis of PDEs · Mathematics 2025-10-20 Viktor I. Korzyuk , Jan V. Rudzko , Vladislav V. Kolyachko

Fitted finite element methods are constructed for a singularly perturbed convection-diffusion problem in two space dimensions. Exponential splines as basis functions are combined with Shishkin meshes to obtain a stable parameter-uniform…

Numerical Analysis · Mathematics 2023-10-03 Alan F. Hegarty , Eugene O'Riordan

Hyperbolic systems of the first and higher-order partial differential equations appear in many multiphysics problems. We will be dealing with a wave propagation problem in a piece-wise homogeneous medium. Mathematically, the problem is…

Analysis of PDEs · Mathematics 2025-03-28 Kayyunnapara Divya Joseph

We provide a numerical algorithm for the model characterizing anomalous diffusion in expanding media, which is derived in [F. Le Vot, E. Abad, and S. B. Yuste, Phys. Rev. E {\bf96} (2017) 032117]. The Sobolev regularity for the equation is…

Numerical Analysis · Mathematics 2020-11-13 Daxin Nie , Jing Sun , Weihua Deng

This work considers the subdiffusion problem with non-positive memory, which not only arises from physical laws with memory, but could be transformed from sophisticated models such as subdiffusion or subdiffusive Fokker-Planck equation with…

Numerical Analysis · Mathematics 2025-05-09 Wenlin Qiu , Xiangcheng Zheng

We derive global analytic representations of fundamental solutions for a class of linear parabolic systems with full coupling of first order derivative terms where coefficient may depend on space and time. Pointwise convergence of the…

Analysis of PDEs · Mathematics 2009-07-17 Joerg Kampen

We consider the problem of approximating the solution of variational problems subject to the constraint that the admissible functions must be convex. This problem is at the interface between convex analysis, convex optimization, variational…

Numerical Analysis · Mathematics 2015-03-19 Adam M. Oberman

Convection-diffusion equations provide the basis for describing heat and mass transfer phenomena as well as processes of continuum mechanics. To handle flows in porous media, the fundamental issue is to model correctly the convective…

Numerical Analysis · Computer Science 2012-08-29 A. Churbanov , P. Vabishchevich

Self-similar solutions of the coherent diffusion equation are derived and measured. The set of real similarity solutions is generalized by the introduction of a nonuniform phase surface, based on the elegant Gaussian modes of optical…

Quantum Physics · Physics 2015-05-19 O. Firstenberg , P. London , D. Yankelev , R. Pugatch , M. Shuker , N. Davidson

This paper is concerned with a strongly degenerate convection-diffusion equation in one space dimension whose convective flux involves a non-linear function of the total mass to one side of the given position. This equation can be…

Numerical Analysis · Mathematics 2010-07-12 Fernando Betancourt , Raimund Bürger , Kenneth H. Karlsen

In this paper we investigate the variable coefficient two-sided fractional diffusion, advection, reaction equations on a bounded interval. It is known that the fractional diffusion operator may lose coercivity due to the variable…

Numerical Analysis · Mathematics 2022-03-23 Xiangcheng Zheng , V. J. Ervin , Hong Wang

We study diffusion processes that are stopped or reflected on the boundary of a domain. The generator of the process is assumed to contain two parts: the main part that degenerates on the boundary in a direction orthogonal to the boundary…

Analysis of PDEs · Mathematics 2023-04-11 Mark Freidlin , Leonid Koralov

In this paper, we are interested in the study of a problem with fractional derivatives having boundary conditions of integral types. The problem represents a Caputo type advection-diffusion equation where the fractional order derivative…

Numerical Analysis · Mathematics 2021-02-23 Saadoune Brahimi , Ahcene Merad , Adem Kilicman