Theorems are proved about the asymptotic behaviour of solutions of an initial boundary-value problem for non-stationary Stokes equations in a periodic perforated domain with a small period epsilon. The viscosity coefficient nu of the equations is assumed to be a positive parameter satisfying one of the following three conditions: nu/epsilon(2) --> infinity, 1, 0 as epsilon --> 0. We also consider the case of degenerate Stokes equations with zero viscosity coefficient and the case of Navier-Stokes equations when the viscosity coefficient is not too small.
