A lattice-gas and lattice Boltzmann study of mixing at continuous fracture junctions: Importance of boundary conditions

Abstract

The lattice-gas automata and lattice Boltzmann (BGK) methods were used to estimate the mixing of fluid streams at a continuous fracture junction, for Peclet number (Pe) from 0 to 1547. Agreement with experimental results is good, particularly at Pe ≤ 25. At low Pe, a large fracture length/width is needed to obtain accurate mixing ratios (Mr). For a 90° intersection of two fractures with equal widths and flow rates, Mr approaches 0.5 (complete mixing) at Pe ≈1. At the highest Pe studied, Mr = 0.022, in contrast with the streamline routing prediction Mr = 0. Copyright 1997 by the American Geophysical Union.