Drop coalescence studies

The objective of this experimental study is to understand the detailed mechanics of the coalescence of liquid drops. The experiments are being conducted in an immiscible acoustic levitator with degassed water as the host medium. Typically, a quasineutrally buoyant drop of silicon oil mixed with bromobenzene is levitated close to the velocity node of the levitator. A second drop of the same liquid is introduced, and as it slowly seeks levitation position, the drops coalesce. Coalescence is delayed until the host film between drops is completely drained. Following coalescence, the excess surface energy in the coalesced drop is dissipated through shape oscillations. The final events of film rupture followed by drop coalescence are rapid and are photographically studied with high-speed video (1000 fps). The laser-induced fluorescence technique is used to visualize the dynamics of host film drainage. The details of the coalescence mechanics are presented

Core-centering of compound drops in capillary oscillations: Observations on USML-1 experiments in space

AA Using the existing inviscid theories, an attempt is made to explain the centering of the oscillating liquid shell. Experiments on liquid shells and liquid-core compound drops were conducted using acoustic levitation, in a low-gravity environment during a Space Shuttle flight. It was observed that their inner and outer interfaces became concentric when excited into capillary oscillations. Using the existing inviscid theories, and attempt is made to explain the centering of the oscillating liquid shell. It is concluded that viscosity needs to be considered in order to provide a realistic description of the centering process

Materials Research Conducted Aboard the International Space Station: Facilities Overview, Operational Procedures, and Experimental Outcomes

The Microgravity Science Glovebox (MSG) and Maintenance Work Area (MWA) are facilities aboard the International Space Station (ISS) that were used to successfully conduct experiments in support of, respectively, the Pore Formation and Mobility Investigation (PFMI) and the In-Space Soldering Investigation (ISSI). The capabilities of these facilities are briefly discussed and then demonstrated by presenting "real-time" and subsequently down-linked video-taped examples from the abovementioned experiments. Data interpretation, ISS telescience, some lessons learned, and the need of such facilities for conducting work in support of understanding materials behavior, particularly fluid processing and transport scenarios, in low-gravity environments is discussed