Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Investigating the migration of immiscible contaminant fluid flow in
  homogeneous and heterogeneous aquifers with high-precision numerical
  simulations   Numerical modeling of the migration of three-phase immiscible fluid flow in
variably saturated zones is challenging due to the different behavior of the
system between unsaturated and saturated zones. This behavior results in the
use of different numerical methods for the numerical simulation of the fluid
flow depending on whether it is in the unsaturated or saturated zones. This
paper shows that using a high-resolution shock-capturing conservative method to
resolve the nonlinear governing coupled partial differential equations of a
three-phase immiscible fluid flow allows the numerical simulation of the system
through both zones providing a unitary vision (and resolution) of the migration
of an immiscible contaminant problem within a porous medium. In particular,
using different initial scenarios (including impermeable 'lenses' in
heterogeneous aquifers), three-dimensional numerical simulation results are
presented on the temporal evolution of the contaminant migration following the
saturation profiles of the three-phases fluids flow in variably saturated
zones. It is considered either light nonaqueous phase liquid with a density
less than the water, or dense nonaqueous phase liquid, which has densities
greater than the water initially released in unsaturated dry soil. Our study
shows that the fate of the migration of immiscible contaminants in variably
saturated zones can be accurately described, using a unique mathematical
conservative model, with different evolution depending on the value of the
system's physical parameters, including the contaminant density, and accurately
tracking the evolution of the sharp (shock) contaminant front.

2
The categories of this paper are: math
17
The categories of this paper are: q-fin
28
The categories of this paper are: alg-geom
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci