ABSTRACT
ABSTRACT: In this paper, the influence of soil heterogeneities and hydraulic Hysteresis as two natural phenomena on simulation of migration and redistribution of heptane’s as a Lighter than water Non-Aqueous Phase Liquid (LNAPL) is demonstrated using a hysteretic three-phase WaterNAPL-Air numerical k-S-P model named ‘‘NAPL’’. The 2D simulations are conducted in a number of dissimilar granular porous media, which consist of a homogeneous medium, and a couple of non-homogeneous binary media that have different characteristics regarding the assignment of divergent soil hydraulic properties and spatial configuration of heterogeneities for each one. In all considered cases vertical and horizontal dimensions of the modeling domain are set respectively to the value of 0.7 m and 0.5 m where a constant spatial step of 1.25 cm used in spatial discretization of both directions. Boundary conditions are imposed specifically to investigate hysteretic k-S-P path behavior. Analysis of the acquired data shows that connivance of Hysteresis or soil heterogeneities through numerical modeling process may lead to significant discrepancies among output results, especially when phase imbibition-drainage history is more sophisticated, although hysteretic modeling of multiphase flow in porous media considering soil heterogeneities needs much more computational requirements and storage regarding the high degree of non-linearity which is accompanied with hysteresis.
