Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Single-phase flow through a porous media revisited   The problem of the flow trough a porous media is formulated in terms of a
pressure equation, based on arguments of volume conservation which state the
mechanical equilibrium between the solid and the fluid phases. In the resulting
governing equations, the conservation of mass is replaced by a
transport-diffusion equation for the pressure field. When the deformation of
the solid matrix is negligible, the pressure equation can be approximated by a
non-linear diffusion equation. The behavior of the system of equations is
tested under an oscillatory pressure gradient.

0
The categories of this paper are: hep-ph
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
6
The categories of this paper are: astro-ph
2
The categories of this paper are: math