3-D flow of a compressible viscous micropolar fluid with spherical symmetry: Regularity of the solution

In this paper we consider the nonstationary 3-D flow of a compressible viscous and heat-conducting micropolar fluid, that is in the thermodynamical sense perfect and polytropic. The fluid domain is a subset of R3 bounded with two concentric spheres that present the solid thermoinsulated walls. The corresponding mathematical model is set up in the Lagrangian description. We assume that the initial data are spherically symmetric functions, and that the initial density and temperature are strictly positive. This problem has a unique spherically symmetric generalized solution globally in time. Here we introduce the Hölder continuous initial functions and prove that, for any T>0, the state function is also Hölder continuous.