Deterministic diffusion in temporally oscillating convection is studied for particles with finite mass. The particles are assumed to obey a simple dissipative dynamical system and the particle diffusion is induced by the strange attractor. The diffusion constants are numerically calculated for convection models with free and rigid boundary conditions.

We probe the diffusive motion of particles in slowly sheared three-dimensional granular suspensions. For sufficiently large strains, the particle dynamics exhibits diffusive Gaussian statistics, with the diffusivity proportional to the local strain rate —consistent with a local, quasistatic picture. Surprisingly, the diffusivity is also inversely proportional to the depth of the particles below...

The process of turbulent mixing across an ideal model of a meandering Gulf Stream is studied considering particle motion in two dimensions. The turbulent motion is modeled using a "random flight" model that assumes that the evolution of the turbulent velocity along trajectories is a Markov process, with the velocity at one time step depending linearly on the velocity at the previous step. This ...

[1] Particle tracking algorithms are very useful methods to model conservative transport in surface and subsurface hydrological systems. Recently, a novel ad hoc particle-based method was proposed to account for multicomponent reactive transport by Benson and Meerschaert (2008). This one-dimensional particle method has been shown to match theoretical predictions, but, to date, there has been no...

A particle tracking code is developed to solve a general time-fractional diffusion equation (FDE), yielding a Lagrangian framework that can track particle dynamics. Extensive simulations demonstrate the efficiency and flexibility of this simple Langevin approach. Many real problems require a vector FDE with variable parameters and multiscaling spreading rates. For these problems, particle track...

Using random walk simulations we explore diffusive transport through monodisperse sphere packings over a range of packing fractions, φ, in the vicinity of the jamming transition at φc. Various diffusion properties are computed over several orders of magnitude in both time and packing pressure. Two well-separated regimes of normal, “Fickian” diffusion, where the mean squared displacement is line...

The interpretation of measurements of the properties of weakly ionized plasmas in terms of diffusion of electrons and ions is reviewed both critically and tutorially. A particular effort is made to tie together various aspects of charged particle diffusion phenomena in quiescent, partially ionized plasmas. The concepts of diffusion length and effective diffusion coefficient and the treatment of...

We set up the Maxwell's equations and subsequently the classical wave equations for the electromagnetic waves which together with the generating source, a traveling oscillatory charge of zero rest mass, comprise a particle traveling in the force field of an usual conservative potential and an additional frictional force f ; these further lead to a classical wave equation for the total wave of t...