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Related papers: Anomalous diffusion in silo drainage

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When particles/molecules diffuse in systems that contain obstacles, the steady-state regime (during which the mean-square displacement scales linearly with time, $\left< r^2 \right> \sim t$) is preceded by a transient regime. It is common…

Biological Physics · Physics 2021-08-12 Nicholas Ilow , Gary W. Slater

We study density fluctuations in supersonic turbulence using both theoretical methods and numerical simulations. A theoretical formulation is developed for the probability distribution function (PDF) of the density at steady state,…

Astrophysics of Galaxies · Physics 2019-09-04 Liubin Pan , Paolo Padoan , Åke Nordlund

Expanding medium is very common in many different fields, such as biology and cosmology. It brings a nonnegligible influence on particle's diffusion, which is quite different from the effect of an external force field. The dynamic mechanism…

Statistical Mechanics · Physics 2023-02-22 Xudong Wang , Yao Chen

In vivo measurements of the passive movements of biomolecules or vesicles in cells consistently report ''anomalous diffusion'', where mean-squared displacements scale as a power law of time with exponent $\alpha< 1$ (subdiffusion). While…

Quantitative Methods · Quantitative Biology 2014-01-27 Hugues Berry , Hugues Chaté

We study non-equilibrium velocity fluctuations in a model for the sedimentation of non-Brownian particles experiencing long-range hydrodynamic interactions. The complex behavior of these fluctuations, the outcome of the collective dynamics…

Statistical Mechanics · Physics 2015-06-24 M. -Carmen Miguel , R. Pastor-Satorras

Microscopic dynamics reveal the origin of the bulk rheological response in complex fluids. In model systems particle motion can be tracked, but for industrially relevant samples this is often impossible. Here we adapt differential dynamic…

Soft Condensed Matter · Physics 2022-02-23 James A. Richards , Vincent A. Martinez , Jochen Arlt

Deriving evolution equations accounting for both anomalous diffusion and reactions is notoriously difficult, even in the simplest cases. In contrast to normal diffusion, reaction kinetics cannot be incorporated into evolution equations…

Statistical Mechanics · Physics 2020-10-23 Sean D Lawley

A numerical study of the role of anomalous diffusion in front propagation in reaction-diffusion systems is presented. Three models of anomalous diffusion are considered: fractional diffusion, tempered fractional diffusion, and a model that…

Pattern Formation and Solitons · Physics 2014-09-11 D. del-Castillo-Negrete

Wang et al. [PNAS 106 (2009) 15160] have found that in several systems the linear time dependence of the mean-square displacement (MSD) of diffusing colloidal particles, typical of normal diffusion, is accompanied by a non-Gaussian…

Statistical Mechanics · Physics 2015-06-19 Mykyta V. Chubynsky , Gary W. Slater

Einstein's explanation of Brownian motion provided one of the cornerstones which underlie the modern approaches to stochastic processes. His approach is based on a random walk picture and is valid for Markovian processes lacking long-term…

Statistical Mechanics · Physics 2009-11-10 I. M. Sokolov , J. Klafter

We introduce a new universality class of one-dimensional iteration model giving rise to self-similar motion, in which the Feigenbaum constants are generalized as self-similar rates and can be predetermined. The curves of the mean-square…

Statistical Mechanics · Physics 2010-05-06 Zhifu Huang , Guozhen Su , Qiuping A Wang , Jincan Chen

Non-Gaussianity indicates complex dynamics related to extreme events or significant outliers. However, the correlation between non-Gaussianity and the dynamics of heterogeneous environments in anomalous diffusion remains uncertain. Inspired…

Soft Condensed Matter · Physics 2023-11-22 Haolan Xu , Xu Zheng , Xinghua Shi

We investigate the dynamic behavior of optical vortices, or phase singularities, in random wavefields and demonstrate the direct experimental observation of the anomalous diffusion of optical vortices. The observed subdiffusion of optical…

Optics · Physics 2023-03-15 Jiaxing Gong , Qi Li , Jing Wang

The scaling invariance for chaotic orbits near a transition from unlimited to limited diffusion in a dissipative standard mapping is explained via the analytical solution of the diffusion equation. It gives the probability of observing a…

Chaotic Dynamics · Physics 2020-12-02 Edson D. Leonel , Celia Mayumi Kuwana , Makoto Yoshida , Juliano Antonio de Oliveira

This Letter provides a theoretical interpretation of numerically generated probability density functions (PDFs) of intermittent plasma transport events. Specifically, nonlinear gyrokinetic simulations of ion-temperature-gradient turbulence…

Plasma Physics · Physics 2010-11-10 Johan Anderson , Pavlos Xanthopoulos

The problem of anomalous diffusion in momentum space is considered for plasma-like systems on the basis of a new collision integral, which is appropriate for consideration of the probability transition function (PTF) with long tails in…

Statistical Mechanics · Physics 2015-05-18 S. A. Trigger , W. Ebeling , G. J. F. van Heijst , P. P. J. M. Schram , I. M. Sokolov

The onset of the Rayleigh-Benard instability in a horizontal fluid layer is investigated by assuming the fluid as a binary mixture and the concentration buoyancy as the driving force. The focus of this study is on the anomalous diffusion…

Fluid Dynamics · Physics 2024-06-18 A. Barletta , B. Straughan

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

Dilute granular flows are routinely described by collisional kinetic theory, but dense flows require a fundamentally different approach, due to long-lasting, many-body contacts. In the case of silo drainage, many continuum models have been…

Statistical Mechanics · Physics 2007-05-23 Martin Z. Bazant

A new method is proposed to numerically extract the diffusivity of a (typically nonlinear) diffusion equation from underlying stochastic particle systems. The proposed strategy requires the system to be in local equilibrium and have…

Statistical Mechanics · Physics 2018-05-09 Peter Embacher , Nicolas Dirr , Johannes Zimmer , Celia Reina