We study the small data global well-posedness and time-decay rates of solutions to the Cauchy problem for 3D compressible Navier-Stokes-Allen-Cahn equations via a refined pure energy method. In particular, the optimal decay rates of the higher-order spatial derivatives of the solution are obtained, the $\dot{ H}^{ -s}$ ($0\leq s<\frac32$) negative Sobolev norms is shown to be preserved along time evolution and enhance the decay rates.
Categories: math.AP