Turbulence generation and liquid breakup were studied because of their relevance to the dense combusting sprays found in propulsion systems. Measurements showed that flows resulting from turbulence generation consisted of drop-wake disturbances embedded in a turbulent inter-wake region and also showed that both regions were unusual: the drop wakes were laminar-like turbulent wakes typical of intermediate Reynolds number wakes in turbulent environments, whereas the turbulent inter-wake region consisted of isotropic turbulence in the little studied final decay period. The properties of both regions were obtained from measurements of monodisperse particle (drop) flows and yielded ways to estimate their properties. New measurements showed the potential effectiveness of modifications of these methods to treat polydisperse particle (drop) flows of greater practical interest. Liquid breakup is important because it is the rate controlling process of dense sprays. Measurements successfully resolved the temporal properties of secondary drop breakup for large liquid/gas density ratios. Numerical simulations provided similar information about the related problem of liquid column breakup with the added advantage of treating small liquid/gas density ratios where measurements were problematic. Corresponding calculations of secondary drop breakup showed interesting similarities between liquid drop and column breakup as well as new ways to treat the effects of density and viscosity variations on breakup.
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