In this work, we present a novel analytical model for tracer dispersion in laminar flow through porous media. Based on a straightforward physical argument, it describes the generic behavior of dispersion over a wide range of Péclet numbers (exceeding eight orders of magnitude). In particular, the model accurately captures the intermediate scaling behavior of longitudinal dispersion, obviating the need to subdivide the dispersional behavior into a number of disjunct regimes or using empirical power-law expressions. The analysis also suggests the possible existence of a new material property, the critical Péclet number, reflecting the mesoscale geometric properties of the microscopic pore structure.
© 2012 American Physical Society