Simulating Scale-Dependent Solute Transport in Soils with the Fractional Advective–Dispersive Equation

摘要: Solute dispersivity defined from the classical advective-dispersive equation (ADE) was found to increase as length of a soil column or depth increased. The heterogeneity is physical reason for this scale dependence. Such transport can be described assuming that random movement solute particles belongs family so-called Levy motions. Recently differential derived motions using fractional derivatives describe advective dispersion. Our objective test applicability ADE, FADE, in soils and compare results FADE ADE applications. one-dimensional with symmetrical dispersion included two parameters: coefficient order differentiation α, 0 ≤ α 2. reduces when parameter Analytical solutions were fitted data experiments on Cl sand, structured clay soil, columns made aggregates. simulated effects tails breakthrough curves (BTCs) better than, well as, ADE. did not depend distance. In column, change significantly flow rate changed provided degree saturation only slightly. With are reflected by derivative, needs he at one scale.