Observation of the shape of a water drop on an oscillating Teflon plate

This is an experimental investigation of the dynamics of water drops under large-amplitude forcing within a frequency range of 10–700 Hz. Water drops on an oscillating horizontal plate displayed various behaviors, such as bouncing, dividing, ejecting, axisymmetric polygonal vibration, and polygonal but not axisymmetric vibration. These last two were alike in that the capillary waves of a water drop gave rise to various polygons. However, the planar directions of the polygons of the non-axisymmetric vibrations seemed stable, and their frequencies were the same as the induced frequencies of the oscillating plate. These two features make non-axisymmetric polygonal vibration different from the axisymmetric polygonal vibration reported to date, and the phenomenon has not yet been successfully analyzed. Trials of simulating some shapes of non-axisymmetric polygonal vibrations according to Rayleigh’s theory are described in this paper.