AN APPARATUS TO STUDY DROP-FORMED VORTEX RINGS

The construction of a novel apparatus to study the formation, evolutio n and decay of vortex rings created by liquid drops impacting upon a l iquid pool is reported. Other phenomena related to drop impact such as the formation of air bubbles due to the collapse of the crater create d by the impact can now also be studied in a controlled environment. T he experiments are performed in a contaminant-free vapour-saturated en vironment, Temperature dependent fluid properties are controlled by a cooling/heating water bath circulated around a completely enclosed flu id reservoir. The experiment is fully automated through a computer int erface to enhance reproducibility. Data are acquired using precisely t imed 35 mm photographs lit by a strobe lamp.