Droplet patterns from capillary stream breakup

Abstract

Droplet patterns have been generated in a vacuum environment by capillary stream breakup initiated by a new form of applied disturbances. The method of producing droplet streams with flexibly controllable patterns is presented. The patterns are periodic sequences of droplets, characterized by specific drop-to-drop separations and diameters. The pattern repeats until the disturbance to the capillary stream is removed or altered. An important feature of this work is that the patterns are deterministic given knowledge of the characteristics of the disturbance waveform. A model has been developed that is based on conservation of momentum and linear theory, and predicts droplet stream configurations with excellent agreement with experiment. Use of spectral analysis demonstrates long-term periodicity and stability of the droplet patterns as well as the excellent agreement between the predicted droplet patterns and those experimentally obtained.