caa a22 4500 606197974 CHVBK 20210128100931.0 cr unu---uuuuu 210128e20150301xx s 000 0 eng 10.1007/s00348-015-1936-4 doi (NATIONALLICENCE)springer-10.1007/s00348-015-1936-4 Mechanism and flow measurement of AC electrowetting propulsion on free surface [Elektronische Daten] [Junqi Yuan, Sung Cho] A free surface in contact with a floating object can be vertically oscillated by applying an alternating current electrowetting-on-dielectric (AC EWOD). The oscillation of the free surface generates a propelling force on the centimeter-sized floating object. This paper describes a propulsion mechanism in free-surface oscillation along with its experimental results. Flow visualizations, wave patterns measured by the free-surface synthetic schlieren method, and PIV measurements show that the oscillation generates a capillary Stokes drift on the water surface and two counter-rotating spiral underwater vortices, leading to an ejecting flow (streaming flow) normal to the wall of the boat. The momentum of the ejecting flow produces a reaction force on the wall and ultimately propels the floating boat. The propulsion speed of the boat highly depends on the amplitude, frequency, and shape of the AC EWOD signal. Curve fittings based on the Stokes drift well match the experimental measurements of propulsion speed. The width of the EWOD electrode also has significant effects on the boat speed. Springer-Verlag Berlin Heidelberg, 2015 Yuan Junqi Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 15261, Pittsburgh, PA, USA aut Cho Sung Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 15261, Pittsburgh, PA, USA aut Experiments in Fluids Springer Berlin Heidelberg 56/3(2015-03-01), 1-10 0723-4864 56:3<1 2015 56 348 https://doi.org/10.1007/s00348-015-1936-4 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00348-015-1936-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yuan Junqi Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 15261, Pittsburgh, PA, USA aut NATIONALLICENCE 700 1- Cho Sung Department of Mechanical Engineering and Materials Science, University of Pittsburgh, 15261, Pittsburgh, PA, USA aut NATIONALLICENCE 773 0- Experiments in Fluids Springer Berlin Heidelberg 56/3(2015-03-01), 1-10 0723-4864 56:3<1 2015 56 348