  In this paper, we study the homogenization of 3D non-homogeneous
incompressible Navier-Stokes system in perforated domains with holes of
critical size. The diameter of the holes is of size \epsilon^3, where \epsilon
is a small parameter measuring the mutual distance between the holes. We show
that when \epsilon tends to 0, the velocity and density converge to a solution
of the non-homogeneous incompressible Navier-Stokes system with a friction term
of Brinkman type.
