On the long-time behavior of solution for compressible Navier-Stokes system with outflow boundary condition

In this paper, we are concerned with the long-time behavior of solution to the barotropic compressible Naiver-Stokes system in three dimensions with physically realistic outflow condition. It is shown that the superposition of a planar boundary layer (both subsonic case and transonic case) and a planar rarefaction wave is time asymptotically stable under small initial perturbation, provided that the magnitude of the stationary solution is sufficiently small, while the wave strength of rarefaction wave may be large. This is the first result on the stability of composite wave patterns for the barotropic compressible Navier-Stokes system in high dimensions with outflow boundary condition. Our approach is based on the nonlinear energy methods.