Electrowetting-on-dielectric (EWOD) induced flow analysis

This note investigates the principle of alternative current electrowetting-on-dielectric (ac-EWOD) driven micropropulsion. When an air-to-water interface is vertically oscillated by ac-EWOD, two different surface waves and underwater flows are generated depending upon the applied frequency. The effects of the frequency are investigated by flow visualization techniques and confirmed by numerical calculations. The results reveal that at a low frequency (1 Hz), the oscillating flows with quasistatic waves are dominant without generating net momentum, whereas at a high frequency (50 Hz), the quasisteady flows with travelling waves are dominant with the generation of net momentum capable of being used for micropropulsion.