Mixing of a generalized Newtonian fluid in a corotating discontinuous
cavity flow is studied. The flow period and the theological coefficien
ts are used as parameters. Using geometrical construction of periodic
orbits and bifurcation analysis we find mixing windows in the paramete
r space. A system within a mixing window is capable of producing unifo
rm mixtures. Some bifurcation values have also been determined. A syst
em whose parameters are in the neighborhood of these values will mostl
y not produce a uniform mixture. The main conclusion is that shear thi
nning degrades mixing in the cavity flow.