On weak D-solutions to the non-stationary Navier–Stokes equations in a three-dimensional exterior domain

In this note we study the Navier–Stokes initial boundary value problem in exterior domains. We assume that the initial data has just finite Dirichlet norm. We call the solution D-solution. It is well known that the analogous steady problem is solved in Galdi (An Introduction to the Mathematical Theory of the Navier–Stokes Equations II. Springer, Berlin, 1994), as well as the existence of time periodic solutions in Maremonti et al. (J Math Sci 93(5):719–746, 1999, Zap. Nauchn. Semin. POMI 233:142–182, 1996). So it is natural to inquire about the case of the nonstationary problem