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Diffusion behaviors of heterogeneous materials are of paramount importance in many engineering problems. Numerical models that take into account the internal structure of such materials are robust but computationally very expensive. This…

Numerical Analysis · Mathematics 2023-12-18 Jan Eliáš , Hao Yin , Gianluca Cusatis

This paper presents a multi-scale method for convection-dominated diffusion problems in the regime of large P\'eclet numbers. The application of the solution operator to piecewise constant right-hand sides on some arbitrary coarse mesh…

Numerical Analysis · Mathematics 2022-06-07 Francesca Bonizzoni , Philip Freese , Daniel Peterseim

We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two indistinguishable fluids. The enhancement of the diffusive transport depends on the system size L and grows…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 A. Donev , A. de la Fuente , J. B. Bell , A. L. Garcia

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

Centered finite-difference discretizations of convection--diffusion equations may oscillate when convection dominates at the mesh scale. For homogeneous Dirichlet problems with constant coefficients on uniform Cartesian grids, we derive…

Numerical Analysis · Mathematics 2026-05-29 Gossrin Jean-Marc Bomisso , Ali Ouattara Kouma

Lithium and sodium are the only solids that are known to lose crystalline order upon cooling. The seemingly-disordered low-temperature phase shows signatures of various close-packed structures. The lack of order has been attributed to a…

Mesoscale and Nanoscale Physics · Physics 2026-02-24 C. M. Wilson , R. Ganesh , K. V. Samokhin

This work presents results of ab-initio simulations of continuous wave transport in disordered absorbing waveguides. Wave interference effects cause deviations from diffusive picture of wave transport and make the diffusion coefficient…

Optics · Physics 2013-05-07 Alexey G. Yamilov , Ben Payne

We consider the homogenisation of a coupled Stokes flow and advection-reaction-diffusion problem in a perforated domain with an evolving microstructure of size $\varepsilon$. Reactions at the boundaries of the microscopic interfaces lead to…

Analysis of PDEs · Mathematics 2024-04-05 Markus Gahn , Malte A. Peter , Iuliu Sorin Pop , David Wiedemann

Recent decades are put lots of efforts to develop a higher-order scheme for convective terms approximation that is stable and reliable. The idea presented here is that approximation approach has to correspond to the physical phenomenon…

Numerical Analysis · Mathematics 2018-10-30 Kiril S. Shterev

Atmospheric water vapour is an essential ingredient of weather and climate. Key features of its distribution can be represented by kinematic models which treat it as a passive scalar advected by a prescribed flow and reacting through…

Atmospheric and Oceanic Physics · Physics 2017-06-29 Yue-Kin Tsang , Jacques Vanneste

Diffusion has been widely used to describe a random walk of particles or waves, and it requires only one parameter -- the diffusion constant. For waves, however, diffusion is an approximation that disregards the possibility of interference.…

Optics · Physics 2014-01-23 Alexey G. Yamilov , Raktim Sarma , Brandon Redding , Ben Payne , Heeso Noh , Hui Cao

We develop a time domain random walk approach for conservative solute transport in heterogeneous media where medium properties vary over a distribution of length scales. The spatial transition lengths are equal to the heterogeneity length…

Fluid Dynamics · Physics 2018-09-05 Tomás Aquino , Marco Dentz

We study the homogenization of a diffusion process which takes place in a binary structure formed by an ambiental connected phase surrounding a suspension of very small spheres distributed in an $\veps$-periodic network. The asymptotic…

Analysis of PDEs · Mathematics 2007-05-23 Fadila Bentalha , Isabelle Gruais , Dan Polisevski

We examine the state of statistical equilibrium attained by a uniformly forced condensable substance subjected to advection in a periodic domain. In particular, we examine the probability density function (\pdf{}) of the condensable…

Pattern Formation and Solitons · Physics 2007-05-23 Jai Sukhatme , Raymond T. Pierrehumbert

This note proposes embedding a time dependent PDE into a convection-diffusion type PDE (in one space dimension higher) with singularity, for which two discretization schemes, the classical streamline-diffusion and the EAFE (edge average…

Numerical Analysis · Mathematics 2016-04-05 Randolph E. Bank , Panayot S. Vassilevski , Ludmil T. Zikatanov

From the smallest biological systems to the largest cosmological structures, spatial domains undergo expansion and contraction. Within these growing domains, diffusive transport is a common phenomenon. Mathematical models have been widely…

Populations and Evolution · Quantitative Biology 2023-06-27 Stuart T. Johnston , Matthew J. Simpson

Time discretization along with space discretization is important in the numerical simulation of subsurface flow applications for long run. In this paper, we derive theoretical convergence error estimates in discrete-time setting for…

Numerical Analysis · Mathematics 2020-03-04 Yerlan Amanbek , Mary Wheeler

In this study, we consider the simulation of subsurface flow and solute transport processes in the stationary limit. In the convection-dominant case, the numerical solution of the transport problem may exhibit non-physical diffusion and…

Numerical Analysis · Mathematics 2023-07-19 A. Q. T. Ngo , P. Bastian , O. Ippisch

In this paper, we are interested in the propagation of convexity by the strong solution to a one-dimensional Brownian stochastic differential equation with coefficients Lipschitz in the spatial variable uniformly in the time variable and in…

Probability · Mathematics 2023-12-18 Benjamin Jourdain , Gilles Pagès

Aggregation-diffusion equations are foundational tools for modelling biological aggregations. Their principal use is to link the collective movement mechanisms of organisms to their emergent space use patterns in a concrete mathematical…

Populations and Evolution · Quantitative Biology 2025-04-16 Jonathan R. Potts