  A coupled system of self-organized hydrodynamics and Navier-Stokes equations
(SOH-NS), which models self-propelled particles in a viscous fluid, was
recently derived by Degond et al. \cite{DMVY-2017-arXiv}, starting from a
micro-macro particle system of Vicsek-Navier-Stokes model, through an
intermediate step of a self-organized kinetic-kinetic model by multiple
coarse-graining processes. We first transfer SOH-NS into a non-singular system
by stereographic projection, then prove the local in time well-posedness of
classical solutions by energy method. Furthermore, employing the Hilbert
expansion approach, we justify the hydrodynamic limit from the self-organized
kinetic-fluid model to macroscopic dynamics. This provides the first
analytically rigorous justification of the modeling and asymptotic analysis in
\cite{DMVY-2017-arXiv}.
