Speaker
Description
Large scale flow and dispersion in heterogeneous networks under non-linear flow conditions
Non-linear flow and dispersion in natural and engineered media are key issues in different fields of science and engineering. Applications range across scales from non-Newtonian flows in pore and capillary networks to turbulent flows in karst networks. Spatial variability in the physical medium properties lead to scale effects in the flow and dispersion processes that manifest in non-Fickian transport and non-Darcian flow behaviors. We study the mechanisms of flow and dispersion in two- and three-dimensional heterogeneous networks under turbulent and non-Newtonian flow conditions, that is, for flows in which the flow rate is a non-linear function of the pressure gradient. The flow fields are characterized statistically in terms of the distribution of Eulerian and Lagrangian flow velocities and their correlation properties with emphasis on the relation between network heterogeneity and flow statistics. Large scale flow is quantified by generalized (non-linear) Darcy and Darcy-Weisbach relations. Solute dispersion is measured in terms of particle breakthrough curves and displacement statistics. We observe broad distributions of particle arrival times and non-linear evolution of the displacement variance, which are manifestations of memory processes that occur due to broadly distributed flow velocities and mass transfer rates. These behaviors are linked to the medium structure and Eulerian flow statistics. Based on this analysis, we propose a stochastic time domain random walk approach to quantify the impact of the network heterogeneity on large-scale flow and dispersion.
| Country | Spain |
|---|---|
| Water & Porous Media Focused Abstracts | This abstract is related to Water |
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