Random walk particle tracking approach to assess 3-D macrodispersion in heterogeneous aquifers

Abstract

A series of solute transport simulations in physically heterogeneous aquifers were conducted to assess the impacts on macrodispersion under saturated flow conditions. The aquifer system of concern relied on the hydrogeological data in a site in the Netherlands and was generated geostatistically as randomly correlated hydraulic conductivity. Ensemble computations in 100 realizations were based upon random walk particle tracking linked with temporal moments to estimate three macrodispersivities. The results showed the scale dependence of macrodispersivities and the asymptotic nature of longitudinal macrodispersivity. From a practical standpoint, the simulations demonstrated that control plane and its middle element provide almost identical macrodispersivity estimates in terms of transverse mixing, but differ markedly from estimates of longitudinal mixing.

Assessing Temporal Moment Characteristics of Solute Transport Phenomena in Heterogeneous Aquifers Using Random Walk Particle Tracking

“…The displacement matrix B in the threedimensional form represents the direction displacement distance for the random process [22], [23] Equilibrium sorption using a linear isotherm can be incorporated by replacing the velocity v with a retarded velocity v/R and D with D/R in Eq. (3) where R is the retardation factor.…”