Ratchet mechanism of drops climbing a vibrated oblique plate

In this paper, we investigate the ratchet mechanism of drops climbing a vibrated oblique plate based on three-dimensional direct numerical simulations, which for the first time reproduce the existing experiment (Brunet et al., Phys. Rev. Lett., vol. 99, 2007, 144501). With the help of numerical simu...

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Bibliographic Details
Published inJournal of fluid mechanics Vol. 835
Main Authors Ding, Hang, Zhu, Xi, Gao, Peng, Lu, Xi-Yun
Format Journal Article
LanguageEnglish
Published Cambridge, UK Cambridge University Press 25.01.2018
Subjects
Acceleration
Climbing
Computer simulation
Contact angle
Experiments
Hydrodynamics
Hysteresis
Inclination
JFM Rapids
Mathematical models
Studies
Theoretical analysis
Vibration
drops
contact lines
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Summary:In this paper, we investigate the ratchet mechanism of drops climbing a vibrated oblique plate based on three-dimensional direct numerical simulations, which for the first time reproduce the existing experiment (Brunet et al., Phys. Rev. Lett., vol. 99, 2007, 144501). With the help of numerical simulations, we identify an interesting and important wetting behaviour of the climbing drop; that is, the breaking of symmetry due to the inclination of the plate with respect to the acceleration leads to a hysteresis of the wetted area in one period of harmonic vibration. In particular, the average wetted area in the downhill stage is larger than that in the uphill stage, which is found to be responsible for the uphill net motion of the drop. A new hydrodynamic model is proposed to interpret the ratchet mechanism, taking account of the effects of the acceleration and contact angle hysteresis. The predictions of the theoretical analysis are in good agreement with the numerical results.
ISSN:0022-1120
1469-7645
DOI:10.1017/jfm.2017.824