Findings from Microgravity Experiments on Low-Speed Water Jet Disintegration

To validate our proposed atomization theory, a series of microgravity experiments were conducted for a water jet issued into an otherwise quiescent atmosphere. The present paper reports findings from the case of liquid Weber number being nearly equal to unity. The water contained in a syringe is pushed by a piston which moves at a constant speed. The initial overshoot of liquid issue speed produces a long water column, whose length is reduced at every instant of subsequent disintegration interacting with the nozzle exit. The balance between tip contraction speed and liquid issue speed, which is attained by the selection of the Weber number, enables us to observe the disintegration process in detail. It is revealed that the short-wave breakup mechanism is characterized as the local destabilization which takes place at the short neck part bridging the tip bulb and the upstream high pressure crest part and that the neck maintains the nature of propagative capillary wave until a final stage of disintegration.