title: Anomalous hydrodynamical dispersion and the transport with multiple families of paths in porous media.
abstract: We investigate a family of probability distributions that shows anomalous hydrodynamic dispersion, by solving a particular class of coupled generalized master equations. The Fourier-Laplace solution is obtained analytically in terms of the matrix Green function method; then the Coats-Smith concentration profile is revisited in a particular case. Two models of disorder are worked out explicitly, and the mean current is asymptotically calculated. We present an approximation method to calculate the first passage time distribution for this stochastic transport process, and as an example an exact Markovian result is worked out; scaling results are also shown. We discuss the comparison with other different methods to work out complex diffusion phenomena in the presence of disordered multiple transport paths. Extensions when the models are nondiffusive can also be solved in the Fourier-Laplace representation.
authors.affiliation: Comisión Nacional de Energía Atómica, Instituto Balseiro, and CONICET, Centro Atómico Bariloche, Rio Negro, 8400 Bariloche, Argentina. caceres@cab.cnea.gov.ar
authors.forename: Manuel O
authors.initials: MO
authors.lastname: Cáceres