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In this paper hyperbolic partial differential equations with random coefficients are discussed. Such random partial differential equations appear for instance in traffic flow problems as well as in many physical processes in random media.…

Analysis of PDEs · Mathematics 2017-06-19 Andrea Barth , Franz G. Fuchs

In this paper we investigate the approximation of a diffusion model problem with contrasted diffusivity and the error analysis of various nonconforming approximation methods. The essential difficulty is that the Sobolev smoothness index of…

Numerical Analysis · Mathematics 2024-12-20 Alexandre Ern , Jean-Luc Guermond

Low-dimensional periodic arrays of scatterers with a moving point particle are ideal models for studying deterministic diffusion. For such systems the diffusion coefficient is typically an irregular function under variation of a control…

Chaotic Dynamics · Physics 2009-11-07 R. Klages , N. Korabel

Simple finite differencing of the anisotropic diffusion equation, where diffusion is only along a given direction, does not ensure that the numerically calculated heat fluxes are in the correct direction. This can lead to negative…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Prateek Sharma , Gregory W. Hammett

The stochastic motion in a nonhomogeneous medium with traps is studied and diffusion properties of that system are discussed. The particle is subjected to a stochastic stimulation obeying a general L\'evy stable statistics and experiences…

Statistical Mechanics · Physics 2015-06-11 Tomasz Srokowski

We study the Possion problem with singular data given by a source supported on a one dimensional curve strictly contained in a three dimensional domain. We prove regularity results for the solution on isotropic and on anisotropic weighted…

Analysis of PDEs · Mathematics 2023-06-02 Ignacio Ojea

The electromagnetic field distribution as well as the resonating frequency of various modes in superconducting cavities used in particle accelerators for example are sensitive to small geometry deformations. The occurring variations are…

Computational Engineering, Finance, and Science · Computer Science 2019-04-09 Niklas Georg , Wolfgang Ackermann , Jacopo Corno , Sebastian Schöps

We study the Brownian motion of a classical particle in one-dimensional inhomogeneous environments where the transition probabilities follow quasiperiodic or aperiodic distributions. Exploiting an exact correspondence with the…

Statistical Mechanics · Physics 2009-10-31 F. Igloi , L. Turban , H. Rieger

We study solution techniques for an evolution equation involving second order derivative in time and the spectral fractional powers, of order $s \in (0,1)$, of symmetric, coercive, linear, elliptic, second-order operators in bounded domains…

Numerical Analysis · Mathematics 2018-06-18 Lehel Banjai , Enrique Otarola

We compare three random field discretization strategies for probabilistic identification of spatially varying material parameters in high-resolution finite element models. These strategies are (i) the Karhunen-Lo\`eve expansion, (ii) a…

Numerical Analysis · Mathematics 2026-05-08 Pieter Vanmechelen , Geert Lombaert , Giovanni Samaey

This paper considers the problem of optimizing the average tracking error for an elliptic partial differential equation with an uncertain lognormal diffusion coefficient. In particular, the application of the multilevel quasi-Monte Carlo…

Numerical Analysis · Mathematics 2021-09-30 Philipp A. Guth , Andreas Van Barel

We analyze the well-posedness of an anisotropic, nonlocal diffusion equation. Establishing an equivalence between weighted and unweighted anisotropic nonlocal diffusion operators in the vein of unified nonlocal vector calculus, we apply our…

Analysis of PDEs · Mathematics 2021-01-13 Marta D'Elia , Mamikon Gulian

We consider frequency-domain acoustic scattering at a homogeneous star-shaped penetrable obstacle, whose shape is uncertain and modelled via a radial spectral parameterization with random coefficients. Using recent results on the stability…

Numerical Analysis · Mathematics 2025-04-14 Ralf Hiptmair , Christoph Schwab , Euan A. Spence

Under nonuniform convection, the distribution of diffusive particles can exhibit dipole and quadrupole anisotropy induced by the fluid inertial and shear force, respectively. These convection-related anisotropies, unlike the Compton-Getting…

High Energy Astrophysical Phenomena · Physics 2022-10-26 Yiran Zhang , Siming Liu , Dejin Wu

The purpose of this paper is to derive anisotropic mean curvature flow as the limit of the anisotropic Allen-Cahn equation. We rely on distributional solution concepts for both the diffuse and sharp interface models, and prove convergence…

Analysis of PDEs · Mathematics 2022-12-23 Tim Laux , Kerrek Stinson , Clemens Ullrich

In the present paper we investigate the inverse problem of identifying simultaneously the diffusion matrix, source term and boundary condition as well as the state in the Neumann boundary value problem for an elliptic partial differential…

Numerical Analysis · Mathematics 2018-01-18 Tran Nhan Tam Quyen

The anisotropic diffusion equation is imperative in understanding cosmic ray diffusion across the Galaxy, the heliosphere, and its interplay with the ambient magnetic field. This diffusion term contributes to the highly stiff nature of the…

High Energy Astrophysical Phenomena · Physics 2022-12-14 Pranab J. Deka , Lukas Einkemmer , Ralf Kissmann

The Van Allen radiation belts in the magnetosphere have been extensively studied using models based on radial diffusion theory, which is based on a quasi-linear approach with prescribed inner and outer boundary conditions. The 1-d diffusion…

We develop a multilevel Monte Carlo (MLMC)-FEM algorithm for linear, elliptic diffusion problems in polytopal domain $\mathcal D\subset \mathbb R^d$, with Besov-tree random coefficients. This is to say that the logarithms of the diffusion…

Numerical Analysis · Mathematics 2023-02-02 Christoph Schwab , Andreas Stein

Enhanced diffusion, which describes the accelerated spread of passive scalars due to the interaction between advection and molecular diffusion, has been extensively studied in simplified geometries, such as uniform shear and radial flows.…

Analysis of PDEs · Mathematics 2024-11-04 Rômulo Damasclin Chaves dos Santos , Jorge Henrique de Oliveira Sales
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