  In this paper, we investigate two dimensional subsonic and subsonic-sonic
spiral flows outside a porous body. The existence and uniqueness of the
subsonic spiral flow are obtained via variational formulation. The optimal
decay rate at far fields is also derived by the Kelvin's transformation and
some elliptic estimates. By extracting spiral subsonic solutions as the
approximate sequences, we obtain the spiral subsonic-sonic limit solution. The
main ingredients of our analysis are methods of calculus of variations, the
theory of second-order quasilinear equations and the compactness framework.
