Non-Fickian transport in heterogeneous media: the role of disorder and spatial correlation
Jueves 16 de noviembre a las 12:15 h
Departamento de Ingeniería del Terreno, Aula CIHS, Planta Baja
Transport of solutes in heterogeneous media is in general non-Fickian. Traditional approaches based on the advection-dispersion equation fail in describing some characteristics of transport such as heavy-tailed breakthrough curves. In the last decades, a great effort has been made in order to show that the continuous time random walk (CTRW) model can effectively reproduce and predict transport in heterogeneous porous media. Nevertheless, several questions remain open. For instance, the impact of disorder and correlation on non-Fickian transport is not completely understood, as well as the mechanisms through which these sources of heterogeneity affect the average transport properties. In particular, understanding the role of spatial correlation is crucial in fractured systems and layered media, where transport is usually super-diffusive due to velocity persistency.
In this seminar, we show how it is possible to use CTRW models to describe transport in d-dimensional media characterised by strong spatial correlation and strong disorder in presence of both advection and diffusion. To quantify the impact of correlation and heterogeneity, we derive analytical solutions for the moments of particle displacements and for the breaktrough curves.