MICROSCOPIC AND MACROSCOPIC DISPERSIONS IN NUMERICALLY GENERATED HETEROGENEOUS POROUS MEDIA

摘要

An evaluation of the dispersion coefficient or the dispersivity is important for the solute transport in groundwater flow. In this paper, an evaluation of the dispersion coefficient by the numerical simulation for the heterogeneous porous media is attempted. The heterogeneous porous media consists of 39 X 19 blocks with the packed glass beads of six different diameters. For each block, microscopic dispersivity, hydraulic conductivity and porosity are known. The forty cases for evaluating the macroscopic dispersion are studied. Specifically, the relationship between the integral scale of the log-transformed hydraulic conductivity and macroscopic dispersivity is examined. It is suggested that the macroscopic dispersion depend on the integral scale and that the sufficiently large observation scale be necessary for obtaining the converged macroscopic dispersion coefficient.