Mixing in a spatially periodic continuous mixer, the partitioned pipe
mixer, is studied using bifurcation analysis with the help of geometri
c construction of periodic orbits and a knowledge of the symmetry of t
he mixing system. Mixing windows, where motion in the mixer is nearly
globally chaotic, are found in the parameter space. Uniform ultimate m
ixtures are expected in the mixing windows as verified with the Poinca
re sections. The present analysis provides a better understanding of t
he existing experimental results.