Significant progress has been made in the following two research areas: (1) Nonlinear spectroscopy of micrometer-size droplets; and (2) Development and application of two- and three- dimensional scalar measurement techniques in flames. In the nonlinear spectroscopy area, the following achievements are reported: (1) Laser-induced shape deformation of transparent droplets by electrostriction, which pushes against the surface tension force and causes the droplet to bulge; (2) Laser-induced shape deformation by heating of absorbing droplets, which were imaged with fluorescence photography; (3) Laser- induced breakdown which quenches the stimulated Raman scattering (SRS); (4) Excitation of SRS with single-mode and multimode Q-switched lasers; and (5) Four-wave mixing processes in droplets, such as third-order sum frequency generation. Achievements in multidimensional scalar imaging include the following: (1) Measurement of the time evolution in premixed H2-air flames using imaging techniques: (2) Development of new techniques for following the time evolution of flow structures in three dimensions; (3) Introduction of a technique for visualizing supersonic flows using Rayleigh scattering from condensed-phase droplets; (4) Measurement of the complete scalar gradient in a nonreacting flow, which allows calculation of the scalar dissipation; (5) Simultaneous CH and CH4 mapping in a turbulent nonpremixed flame, and (6) Investigation of differential diffusion effects.

Partial contents: Supercritical droplet behavior; Fundamentals of acoustic instabilities in liquid-propellant rockets; Modeling liquid jet atomization proceses; Liquid-propellant droplets dynamics and combustions in supercritical forced convective environments; Contributions of shear coaxial injectors to liquid rocket motor combustion instabilities; High pressure combustion studies under combustion driven oscillatory flow conditions; Droplet collision on liquid propellant combustion; Combustion and plumes; Development of a collisional radiative emission model for strongly nonequilibrium flows; Energy transfer processes in the production of excited states in reacting rocket flows; modeling nonequilibrium radiation in high altitude plumes; kinetics of plume radiation, and of HEDMs and metallic fuels combustion; Nonsteady combustion mechanisms of advanced solid propellants; Chemical mechanisms at the burning surface. p15