Tunable Transport of Drops on a Vibrating Fiber

Abstract

Transport of liquid drops on a fibrous medium is common in diverse engineering systems including fog harvesting and textile cleaning. The precise control of drop movement can increase system efficiency and enable new engineering applications. We investigated how controlling fiber vibration, using standing waves, results in drop movement along a single inclined fiber focusing on fiber inclination angle, drop volume, and wave amplitude. We observe three drop states: static, sliding or falling. By vibrating the fiber the transition between the three drop motion states can be controlled. In particular, the dripping transition is successfully predicted theoretically. Using predictions from this model, we experimentally demonstrated that vibration frequency can be used to controllably transport a drop along a fiber. This knowledge is directly useful for controlling drop movement in numerous engineering applications.