  The dual fluid description for a general cutoff surface at radius r=r_c
outside the horizon in the charged AdS black brane bulk space-time is
investigated, first in the Einstein-Maxwell theory. Under the non-relativistic
long-wavelength expansion with parameter \epsilon, the coupled Einstein-Maxwell
equations are solved up to O(\epsilon^2). The incompressible Navier-Stokes
equation with external force density is obtained as the constraint equation at
the cutoff surface. For non-extremal black brane, the viscosity of the dual
fluid is determined by the regularity of the metric fluctuation at the horizon,
whose ratio to entropy density \eta/s is independent of both the cutoff r_c and
the black brane charge. Then, we extend our discussion to the
Gauss-Bonnet-Maxwell case, where the incompressible Navier-Stokes equation with
external force density is also obtained at a general cutoff surface. In this
case, it turns out that the ratio \eta/s is independent of the cutoff r_c but
dependent on the charge density of the black brane.
