  We consider two-level finite element discretization methods for the stream
function formulation of the Navier-Stokes equations. The two-level method
consists of solving a small nonlinear system on the coarse mesh, then solving a
linear system on the fine mesh. The basic result states that the errors between
the coarse and fine meshes are related superlinearly. This paper demonstrates
that the two-level method can be implemented to approximate efficiently
solutions to the Navier-Stokes equations. Two fluid flow calculations are
considered to test problems which have a known solution and the driven cavity
problem. Stream function contours are displayed showing the main features of
the flow.
