Bubble dispersion and interphase coupling in a free-shear flow

The interaction of a dilute dispersed cloud of microbubbles with a planar f ree-shear layer is investigated experimentally The emphasis of this study i s on the role of the coherent large scales of the flow in the bubble disper sion field and the energy redistribution within the carrier phase. The inte rphase momentum transfer integrals that appear in the volume-averaged momen tum and energy equations account for redistribution of energy from potentia l to kinetic within the carrier phase. This results from both the hydrostat ic and dynamic pressure fields. The energy redistribution within the carrie r phase that is associated with the large-scale structures of the flow poss esses significant inhomogeneities within the mixing layer. Peaks of enhance d kinetic energy generation are associated with the upwelling regions at th e downstream edge of the coherent vortex cores, and weaker peaks of kinetic energy destruction are associated with downwelling regions. The contributi on of the quasi-steady drag term to the total energy redistribution is foun d to be dominant in only a limited region of the flow field.