3-DIMENSIONAL CHAOTIC MIXING OF FLUIDS IN A CYLINDRICAL CAVITY

Three-dimensional chaotic mixing of Newtonian fluids in a previously u ninvestigated cylindrical cavity was studied both experimentally and n umerically for creeping flow conditions, Such mixing processes have pr actical application to the blending of viscous fluids, biological susp ensions, or can be risen as test beds to study waterborne pollutant fo rmation. A mixing chamber was fabricated which consisted of a cylindri cal glass cavity with independently rotating upper and lower circular disks. Fluid motion was revealed by digitizing successive video images of a small neutrally buoyant sphere placed into the mixing cavity and also by photographing dyed blobs. Experimental particle tracking stud ies were supplemented by numerical simulations. Phase-space trajectori es, return maps, and Lyapunov exponents were used to characterize the mixing process and to confirm chaotic behavior.