Speaker
Description
We analyze solute transport in partially saturated porous media in the presence of adsorption and desorption processes. Starting from experimental images of the water-air distribution in a millifluidic device [1], we perform pore-scale simulations of water-phase flow and solute transport, accounting for adsorption and desorption at grain surfaces. We explore a range of transport regimes defined by the Péclet number, the adsorption/desorption Damköhler number, and the degree of saturation. The macroscopic response is characterized through solute breakthrough curves (BTCs) and linked to the underlying pore-scale dynamics. We find that, at increasing Péclet numbers, adsorption and desorption induce a two-stage delay in the BTC: solute transport is first retarded along preferential flow paths and later in slow-flow regions. This effect becomes more pronounced at low saturation, where preferential pathways and stagnant pockets are more clearly segregated.
| References | Jiménez‐Martínez, J., Le Borgne, T., Tabuteau, H., & Méheust, Y. (2017). Impact of saturation on dispersion and mixing in porous media: Photobleaching pulse injection experiments and shear‐enhanced mixing model. Water Resources Research, 53(2), 1457-1472 |
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| Country | Italia |
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