Mixing of viscous polymer liquids

A torsionally driven cavity is proposed as a suitable mixing device for vis coelastic fluids. "Chaotic" behavior occurs in the secondary flow plane usi ng polyacrylamide Boger fluids due to the inducement of elastic flow instab ilities in situations where inertial forces are small. The torsionally driv en cavity is also a suitable well-defined geometry for testing the ability of non-Newtonian constitutive models to describe the behavior of elastic fl uids in three-dimensional flow as a prelude to solving more difficult mixin g problems. (C) 2000 American Institute of Physics. [S1070-6631(00)01406-9] .