Displacement of droplets on a vibrating structure.

A water droplet placed on a vibrating surface moves toward the antinode of the vibration. The acoustic radiation pressure can explain this non-linear phenomenon. In this paper, the use of a piezoelectric actuator to produce a displacement of liquid droplets is pointed out. Due to geometry of the actuator and the position of piezoelectric ceramics, it is possible to generate stationary modes in the structure where the nodal lines can move.