| Liquid film motor (suspended liquid film in crossing electric fields) as a novel exper-imental device will play an important role in basic research and technology applications. In-depth theoretical studies on its electro-hydrodynamics (EHD) motions under various conditions are of great significance. In current paper, the dynamical characteristics of sus-pended liquid film driven by various crossed electric fields are investigated theoretically. Supposing the liquid film in an external electric field as a Bingham plastic fluid with equiv-alent electric dipole moment, a simple dynamical model to systemically explain the rotation mechanism of the liquid film motor reported by experiments is constructed. Several analytic results involving the torques induced EHD motions, the scaling relation of the threshold fields, and the dynamics equation of a square film and its general solution are obtained. The model systemically presents the dynamical characteristics of suspended liquid film lo-cated in crossed direct current fields and alternating current fields. The theoretical results are consistent well with experimental results. By generalizing this model, it predicts the electro-dynamical characteristics of the film driven by other types electric fields. Our study provided solid theoretical foundation for it’s application in the micro-fluidic systems. |
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