Compressible Stokes Problem on Nonconvex Polygonal Domains

The compressible Stokes system with the inflow boundary condition is studied on the polygonal domain D. It is shown that the lowest order corner singularity of the system is the same as that of the Laplacian. The velocity u is split into a singular and regular part near each concave vertex. If the polygon is convex, it is shown that u (H2(D))2.