Max Planck Institute for Dynamics and Self-Organization -- Department for Nonlinear Dynamics and Network Dynamics Group
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BCCN Sonderseminar

Wednesday, 20.08.2008 17 c.t.

An effective model for non-Fickian transport in crowded environments

by Dr. Marco Dentz
from Department of Geotechnical Engineering and Geosciences, Technical University of Catalonia (UPC), Barcelona, Spain

Contact person: Armin Biess


Seminarraum Haus 2, 4. Stock (Bunsenstr.)


Microscale retention mechanisms in crowded media such as dead end pores and sorption-desorption reactions can cause non-Fickian transport features such as anomalous dispersion and non-Gaussian first passage time distributions. Here we analyze an idealized microscale transport model that is characterized by a spatially distributed retardation coefficient. We coarse grain transport in a Lagrangian framework. The upscaled Lagrangian transport equation describes the effective particle motion as a random walk in space-time, or in other words, a continuous time random walk, which is characterized by a joint transition length and time distribution. The transition time distribution is obtained by an exact map from the spatial distribution of microscale retardation coefficients. The effective model compares well with direct numerical simulations of the microscale transport problem and can explain and model non-Fickian transport in crowded environments.

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