A vacuum problem for multidimensional compressible Navier-Stokes equations with degenerate viscosity coefficients

Abstract

Local solutions of the multidimensional Navier-Stokes equations for isentropic compressible flow are constructed with spherically symmetric initial data between a solid core and a free boundary connected to a surrounding vacuum state. The viscosity coefficients $\hat{I}»,\hat{I}¼$ are proportional to $ρ^θ}$, $0<\hat{I}¸<{\hat{I}}^3$, where $\ddot{I}$ is the density and ${\hat{I}}^3>1$ is the physical constant of polytropic fluid. It is also proved that no vacuum develops between the solid core and the free boundary, and the free boundary expands with finite speed.

32 pages