Disparity of Macrodispersivity Estimated from Temporal and Spatial Moments Using Random Walk Particle Tracking in Heterogeneous Porous Formations

抄録

This paper presents advective and dispersive solute transport processes in naturally heterogeneous porous formations based on a random walk particle tracking method. Specifically, the disparity of macrodispersivities estimated from temporal moments of breakthrough curves at control planes and from spatial moments of particle cloud is investigated in non-uniform flow systems under the three different conditions of hydraulic conductivity distributions. For both temporal and spatial moment approaches, longitudinal macrodispersivity estimates in stratum porous formations are in considerable agreement with the results reported in the literature. The disparity of macrodispersivity attributes to the nature of both approaches to evaluate a travel distance of particle plume. While the second central temporal moments in stratum aquifer asymptotically approach a constant value regardless of the injection and pumping rates at active wells, the behavior of the second spatial moments depends upon the porous formations and pumping rates. Furthermore, spatial moment approach represents a potentially valuable tool in the assessment of transverse macrodispersion process in heterogeneous porous media.