HR: 17:30h
AN: H34A-07    [Abstracts]
TI: Dispersion in Porous Media from Pore-scale Network Simulation
AU: * Bijeljic, B
EM: b.bijeljic@imperial.ac.uk
AF: Imperial College, Department of Earth Science and Engineering South Kensington Campus , London, SW7 2AZ United Kingdom
AU: Muggeridge, A H
EM: a.muggeridge@imperial.ac.uk
AF: Imperial College, Department of Earth Science and Engineering South Kensington Campus , London, SW7 2AZ United Kingdom
AU: Blunt, M J
EM: m.blunt@imperial.ac.uk
AF: Imperial College, Department of Earth Science and Engineering South Kensington Campus , London, SW7 2AZ United Kingdom
AB: We study macroscopic (~cm to ~m scale) dispersion using pore-scale network simulation. A Lagrangian-based transport model incorporating flow and diffusion is applied in a diamond lattice of throats with square cross-section whose radius distribution is the same as computed for Berea sandstone. We use physically consistent rules using a combination of stream-tube routing and ideal mixing to transport particles across pore junctions. Asymptotic behavior is only being seen after movement through many throats. The approach to asymptotic behaviour is analysed by looking at the distribution of transit times between pores and is found to be dependent on heterogeneity and Peclet number. A comprehensive comparative study of longitudinal and transverse dispersion with experiments in consolidated and unconsolidated media indicates that the model can quantitatively predict the asymptotic macroscopic dispersion coefficients over a broad range of Peclet numbers, 0 $<$ Pe $<$ 100000. We discuss the correlation between longitudinal and transverse dispersion coefficients.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting