Methods for determining transverse dispersion coefficients of porous media in laboratory column experiments

Abstract

Continuous point source and instantaneous finite source methods are presented for determining the transverse dispersion coefficient of saturated porous media in laboratory column experiments. The methods entail injecting a conservative tracer from an injector embedded in a porous medium, monitoring concentration variations with time within the column upgradient from where the tracer impinges on the column wall, and extracting longitudinal and transverse dispersion coefficient values from relative concentration‐time data using three‐dimensional advection‐dispersion formulations. The methods were tested in a column packed with glass beads for comparison with reported flow tank tests. The transverse dispersion coefficient values calculated using column test data agree closely with flow tank results. The methods presented offer new approaches for investigating dispersion phenomena in porous media and especially offer the potential for determining the transverse as well as the longitudinal dispersion coefficient of undisturbed core samples.