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Surfing the capillary wave: Wetting dynamics beneath an impacting drop

John M. Kolinski1, Ramin Kaviani1, Dylan Hade1, and Shmuel M. Rubinstein2

  • 1École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
  • 2The Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA

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Phys. Rev. Fluids 4, 123605 – Published 24 December, 2019

DOI: https://doi.org/10.1103/PhysRevFluids.4.123605

Abstract

The initiation of contact between liquid and a dry solid is of great fundamental and practical importance. We experimentally probe the dynamics of wetting that occur when an impacting drop first contacts a dry surface. We show that, initially, wetting is mediated by the formation and growth of nanoscale liquid bridges, binding the liquid to the solid across a thin film of air. As the liquid bridge expands, air accumulates and deforms the liquid-air interface, and a capillary wave forms ahead of the advancing wetting front. This capillary wave regularizes the pressure at the advancing wetting front and explains the anomalously low wetting velocities observed. As the liquid viscosity increases, the wetting front velocity decreases; we propose a phenomenological scaling for the observed decrease of the wetting velocity with liquid viscosity.

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Phys. Rev. Fluids 4, 123605– Published 24 December, 2019
  • Received 8 October 2015
Article part of CHORUS
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