Mixing Dynamics in Interacting Vortices

Mixing dynamics arising from the interaction of two convecting line vortices of different strengths and time delays have been investigated in this chapter. Experimentally obtained planar laser induced fluorescence images of acetone vortices mixing in air are thoroughly substantiated with computational modeling and analysis. Same and opposite direction of rotation, generating vortex pairs and couples were found to augment and dissipate species mixing respectively as indicated by global scalar statistics like mean and variance. Local mixing characteristics are analyzed using joint probability density function of vorticity and species concentration. This quantitatively showed how mixing is dissipated or augmented for individual vortices and at different vorticity magnitudes, even by the decaying and apparently indiscernible presence of a favorable or unfavorable direction of rotation of the preceding vortex.