  We present measurements of quasi-Keplerian flows in a Taylor-Couette device
that identify the boundary conditions required to generate near-ideal flows
that exhibit self-similarity under scaling of the Reynolds number. These
experiments are contrasted with alternate boundary configurations that result
in flows that progressively deviate from ideal Couette rotation as the Reynolds
number is increased. These behaviors are quantitatively explained in terms of
the tendency to generate global Ekman circulation and the balance of angular
momentum fluxes through the axial and radial boundary layers.
