Abstract
A horizontally oriented glass pipe containing partially filled silicone oil or ethanol was dropped using the drop shaft facility of Japan Microgravity Center (JAMIC). The behavior of the liquid in the transient period from normal gravity to microgravity was observed with a CCD camera, and the velocity of the silicone oil flow was measured with a particle imaging velocimetry (PIV) based on the cross-correlation method . Just after the glass pipe was set in microgravity, the horizontal gas-liquid interface was deformed strongly and the liquid was transformed into liquid plugs. According to the velocity measurements and eye inspection of video images, the flow establishment time required to form the liquid plugs completely in the glass pipe was determined, and an empirical equation was derived for the flow establishment time.
