Scalar perturbation of the viscosity dark fluid cosmological model
  A general equation of state is used to model unified dark matter and dark
energy (dark fluid), and it has been proved that this model is equivalent to a
single fluid with time-dependent bulk viscosity. In this paper, we investigate
scalar perturbation of this viscosity dark fluid model. For particular
parameter selection, we find that perturbation quantity can be obtained exactly
in the future universe. We numerically solve the perturbation evolution
equations, and compare the results with those of $\Lambda$CDM model.
Gravitational potential and the density perturbation of the model studied here
have the similar behavior with the standard model, though there exists
significant value differences in the late universe.
