ROLE OF LOBES IN CHAOTIC MIXING OF MISCIBLE AND IMMISCIBLE IMPURITIES

Experiments compare long-range chaotic mixing of miscible and immiscib le impurities in a time-periodic flow. For the miscible case, the tran sport is enhanced diffusion with an effective diffusion constant deter mined by lobes (turnstiles) that carry impurities between vortices. Fo r the immiscible case, the impurity is broken into a distribution of d roplets. If the characteristic droplet size is appreciably smaller tha n the lobe size, the transport is equivalent to that from the miscible case. Otherwise, interfacial tension results in reduction (and possib ly extinction) of the transport.