title: Propulsion mechanisms for Leidenfrost solids on ratchets.
abstract: We propose a model for the propulsion of Leidenfrost solids on ratchets based on viscous drag due to the flow of evaporating vapor. The model assumes pressure-driven flow described by the Navier-Stokes equations and is mainly studied in lubrication approximation. A scaling expression is derived for the dependence of the propulsive force on geometric parameters of the ratchet surface and properties of the sublimating solid. We show that the model results as well as the scaling law compare favorably with experiments and are able to reproduce the experimentally observed scaling with the size of the solid.
authors.affiliation: Center of Smart Interfaces, TU Darmstadt, Germany. baier@csi.tu-darmstadt.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Baier
authors.forename: Guillaume
authors.initials: G
authors.lastname: Dupeux
authors.forename: Stefan
authors.initials: S
authors.lastname: Herbert
authors.forename: Steffen
authors.initials: S
authors.lastname: Hardt
authors.forename: David
authors.initials: D
authors.lastname: Quéré
mesh_terms: D003198:Computer Simulation; D017276:Friction; D005740:Gases / Q000737:chemistry*; D008956:Models, Chemical; D009038:Motion; D012212:Rheology / Q000379:methods*; D013314:Stress, Mechanical; D014783:Viscosity
chemical_list: D005740:Gases