  The dynamics of a spinning fluid in a flat cosmological model is
investigated. The space-time is itself generated by the spinning fluid which is
characterized by an energy-momentum tensor consisting a sum of the usual
perfect-fluid energy-momentum tensor and some Belinfante-Rosenfeld tensors. It
is shown that the equations of motion admit a solution for which the fluid
four-velocity and four-momentum are not co-linear in general. The momentum and
spin densities of the fluid are expressed in terms of the scale factor.
