Propulsion mechanisms for Leidenfrost solids on ratchets

Tobias Baier (1) , Guillaume Dupeux (2, 3) , Stefan Herbert (4) , Steffen Hardt (1) , David Quéré (2, 3)

1 Center of Smart Interfaces
2 LadHyX - Laboratoire d'hydrodynamique
3 PMMH - Physique et mécanique des milieux hétérogenes (UMR 7636)
4 Technische Thermodynamik

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. DOI: 10.1103/PhysRevE.87.021001

Domains: Fluid mechanics [physics.class-ph]; Fluids mechanics [physics.class-ph]

Tobias Baier, Guillaume Dupeux, Stefan Herbert, Steffen Hardt, David Quéré. Propulsion mechanisms for Leidenfrost solids on ratchets. Physical Review E : Statistical, Nonlinear, and Soft Matter Physics, 2013, 87 (2), pp.021001(R). ⟨10.1103/physreve.87.021001⟩. ⟨hal-00996480⟩