A method-of-moments scheme is invoked to compute the asymptotic, long-time mean (or composite) velocity and dispersivity (effective diffusivity) of a two-state particle undergoing one-dimensional convectivediffusive motion accompanied by a reversible linear transition (“chemical reaction” or “change in phase”) between these states. The instantaneous state-specific particle velocity is assumed t...

Anomalous dispersion is observed throughout hydrology, yielding a contaminant plume with heavy leading tails. The fractional advection dispersion equation (FADE) captures this behavior by replacing the second-order spatial derivative with a Riemann-Liouville (RL) fractional derivative. The RL fractional derivative is a nonlocal operator and models large jumps of solute particles in heterogeneou...

The study deals with the introduction of coherent imaging ideas in the kinetic analysis of systems. It is developed in the radar context and is devoted to the description of general targets exhibiting motion, scintillation and dispersivity. This description is based on a physical model of small independent reflectors which can be moving and non-permanent. The resulting representations are gener...

Spreading of a conservative solute in potential flow in a helical porous medium is dominated by the radial velocity distribution within the domain. Higher velocities at the inside of the helix compared to the outside leads to spreading that is balanced by transverse pore-scale dispersion. The angular moments of the concentration distribution exhibit the typical behavior of Taylor-Aris dispersio...