Dispersion in double-porosity unsaturated medium: from experiment towards modeling by homogenization

International audienceThis study presents a macroscopic double-porosity dispersion model for unsaturated water flow conditions, developed by asymptotic homogenization method. The model shows a coupling between the concentrations in the micro- and macro-porosity domains (local non-equilibrium), resulting in an early breakthrough and a long tail effects. A series of one-dimensional dispersion experiments of passive tracer under unsaturated steady-state flow conditions in a physical model of double-porosity material, was performed. An excellent agreement between the numerical simulations and the experiments proves good predictive capacity of the developed model