title: Liquid drop runs upward between two nonparallel plates.
abstract: We have recently observed an interesting phenomenon: even under gravity, a microliter-scaled silicone oil drop was still able to run upward between two nonparallel plates that were approximately vertically placed. We also saw the same phenomenon in the case of isopropyl alcohol (IPA) drops. In this work, we developed simple models to interpret this phenomenon, followed by experimental validation. We demonstrated that, by changing the locations of drops or tilt and opening angles of plates, the moving directions of silicone oil, IPA, and water drops could be controlled. In the cases of silicone oil and IPA, we also found that the speed of a drop had a linear relation with the square of the drop location when the drop was far away from the corner of two nonparallel plates and that the drop moved faster as it became closer to this corner.
authors.affiliation: Department of Mechanical and Aerospace Engineering, University of Texas at Arlington , 500 West First Street, Woolf Hall 226, Arlington, Texas 76019, United States.
authors.forename: Xin
authors.initials: X
authors.lastname: Heng
authors.forename: Cheng
authors.initials: C
authors.lastname: Luo