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We consider the homogenization of a model of reactive flows through periodic porous media involving a single solute which can be absorbed and desorbed on the pore boundaries. This is a system of two convection-diffusion equations, one in…

Analysis of PDEs · Mathematics 2014-12-30 Grégoire Allaire , Harsha Hutridurga

A version of fractional diffusion on bounded domains, subject to 'homogeneous Dirichlet boundary conditions' is derived from a kinetic transport model with homogeneous inflow boundary conditions. For nonconvex domains, the result differs…

Analysis of PDEs · Mathematics 2016-07-05 Pedro Aceves-Sanchez , Christian Schmeiser

We prove the existence of an eddy heat diffusion coefficient coming from an idealized model of turbulent fluid. A difficulty lies in the presence of a boundary, with also turbulent mixing and the eddy diffusion coefficient going to zero at…

Mathematical Physics · Physics 2022-02-08 Franco Flandoli , Lucio Galeati , Dejun Luo

We prove uniqueness of a martingale problem with boundary conditions on a simplex associated to a differential operator with an unbounded drift. We show that the solution of the martingale problem remains absorbed at the boundary once it…

Probability · Mathematics 2015-05-06 J. Beltrán , M. Jara , C. Landim

Interactions between an evolving solid and inviscid flow can result in substantial computational complexity, particularly in circumstances involving varied boundary conditions between the solid and fluid phases. Examples of such…

Fluid Dynamics · Physics 2022-09-30 Emma M. Schmidt , J. Matt Quinlan , Brandon Runnels

We consider a two-component competition-diffusion system with equal diffusion coefficients and inhomogeneous Dirichlet boundary conditions. When the interspecific competition parameter tends to infinity, the system solution converges to…

Analysis of PDEs · Mathematics 2007-07-13 E. C. M. Crooks , E. N. Dancer , D. Hilhorst

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

We propose certain approach of solving two-dimensional non-stationary and stationary advection-diffusion-reaction boundary value problems through their reduction to the set of corresponding one-dimensional problems. This method leverages…

Numerical Analysis · Mathematics 2024-11-19 R. Drebotiy , H. Shynkarenko

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

We construct four variants of space-time finite element discretizations based on linear tensor-product and simplex-type finite elements. The resulting discretizations are continuous in space, and continuous or discontinuous in time. In a…

Numerical Analysis · Mathematics 2024-09-05 Max von Danwitz , Igor Voulis , Norbert Hosters , Marek Behr

This paper derives physically meaningful boundary conditions for fractional diffusion equations, using a mass balance approach. Numerical solutions are presented, and theoretical properties are reviewed, including well-posedness and steady…

Analysis of PDEs · Mathematics 2017-06-27 Boris Baeumer , Mihály Kovács , Mark M. Meerschaert , Harish Sankaranarayanan

We prove the existence of a traveling wave solution for a boundary reaction diffusion equation when the reaction term is the combustion nonlinearity with ignition temperature. A key role in the proof is plaid by an explicit formula for…

Analysis of PDEs · Mathematics 2011-01-25 L. Caffarelli , A. Mellet , Y. Sire

We determine the asymptotic spreading speed of an invasive species, which invades the territory of a native competitor, governed by a diffusive competition model with a free boundary in a spherically symmetric setting. This free boundary…

Analysis of PDEs · Mathematics 2015-06-19 Yihong Du , Mingxin Wang , Maolin Zhou

We study the diffusion (or heat) equation on a finite 1-dimensional spatial domain, but we replace one of the boundary conditions with a "nonlocal condition", through which we specify a weighted average of the solution over the spatial…

Analysis of PDEs · Mathematics 2017-08-04 Peter D. Miller , David A. Smith

Diffuse domain methods (DDMs) have garnered significant attention for approximating solutions to partial differential equations on complex geometries. These methods implicitly represent the geometry by replacing the sharp boundary interface…

Analysis of PDEs · Mathematics 2025-04-25 Toai Luong , Tadele Mengesha , Steven M. Wise , Ming Hei Wong

The existence of global weak solutions to a parabolic energy-transport system in a bounded domain with no-flux boundary conditions is proved. The model can be derived in the diffusion limit from a kinetic equation with a linear collision…

Analysis of PDEs · Mathematics 2023-07-18 Gianluca Favre , Ansgar Jüngel , Christian Schmeiser , Nicola Zamponi

Many physical systems of interest involve the close interaction of a flow in a domain with complex, time-varying boundaries. Treatment of boundaries of this nature is cumbersome due to the difficulty in explicitly tracking boundaries that…

Fluid Dynamics · Physics 2025-02-25 Emma M. Boyd , Eric Sandall , Maycon Meier , J. Matt Quinlan , Brandon Runnels

How many times a diffusing molecule can permeate across a membrane or be adsorbed on a substrate? We employ the encounter-based approach to find the statistics of adsorption or permeation events for molecular diffusion in a general…

Chemical Physics · Physics 2025-07-15 Denis S. Grebenkov

This is part II of our study on the free boundary problems with nonlocal and local diffusions. In part I, we obtained the existence, uniqueness, regularity and estimates of global solution. In part II here, we show a spreading-vanishing…

Analysis of PDEs · Mathematics 2019-11-28 Jianping Wang , Mingxin Wang

We consider single-file diffusion in an open system with two species $A,B$ of particles. At the boundaries we assume different reservoir densities which drive the system into a non-equilibrium steady state. As a model we use an…

Statistical Mechanics · Physics 2007-05-23 A. Brzank , G. M. Schütz