It is of utmost importance to note that the Sound-Space approach to subsonic compressibility effects is an exact solution to the problem. That is, equation 19.5 is an exact relation between the compressible and incompressible local pressure coefficients. Nowhere in the preceding analysis was it necessary to make simplifying assumptions such as small perturbations, etc. It is true that the Sound-Space Theory assumes steady reversible–adiabatic flow and consequently it is to be expected that there will be discrepancies in the calculated and experimental values. The validity of the physical principles upon which the Sound~Space Theory was founded and the consequent exact solution to the problem of subsonic compressibility effects, should signify an important advance to the better understanding of compressable fluid phenomena. / Master of Science

When confined within containers or conduits, drops and bubbles migrate to regions of minimum energy by the combined effects of surface tension, surface wetting, system geometry, and initial conditions. Such capillary phenomena are exploited for passive phase separation operations in micro-fluidic devices on earth and macro-fluidic devices aboard spacecraft. Our study focuses on the migration and ejection of large inertial-capillary drops confined between tilted planar hydrophobic substrates. In our experiments, the brief nearly weightless environment of a drop tower allows for the study of such capillary dominated behavior for up to 10 mL water drops with migration velocities up to 12 cm/s. We control ejection velocities as a function of drop volume, substrate tilt angle, initial confinement, and fluid properties. We then demonstrate how such geometries may be employed as passive no-moving-parts droplet generators for very large drop dynamics investigations. The method is ideal for hand-held non-oscillatory drop generation for fun, educational, and insightful astronaut demonstrations aboard the International Space Station.

Results are shown on page 47 in a table. / Master of Science