Article
Near-Field Acousto Monitoring Shear Interactions Inside a Drop of Fluid: The Role of the Zero-Slip condition
Physics of Fluids
(2016)
Abstract
A full understanding of nanometer-range (near-field) interactions between two sliding solid boundaries, with a mesoscopic fluid layer sandwiched in between, remains challenging. In particular, the origin of the blue-shift resonance frequency experienced by a laterally oscillating probe when approaching a substrate is still a matter of controversy. A simpler problem is addressed here, where a laterally oscillating solid probe interacts with a more sizable drop of fluid that rests on a substrate, aiming at identifying interaction mechanisms that could also be present in the near-field interaction case. It is found that the inelastic component of the probe-fluid interaction does not constitute the main energy-dissipation channel and has a weak dependence on fluid’s viscosity, which is attributed to the zero-slip hydrodynamic condition. In contrast, the acoustic signal engendered by the fluid has a stronger dependence on the fluid’s viscosity(attributed also to the zero-slip hydrodynamic condition) and correlates well with the probe’s resonancefrequency red-shift. We propose a similar mechanism happens in near field experiments, but a blue-shift in the probe’s resonance results as a consequence of the fluid molecules (subjected to the zero-slip condition at both the probe and substrate boundaries) exerting instead a spring type restoring force on the probe.
Disciplines
Publication Date
May, 2016
DOI
10.1063/1.4947597
Publisher Statement
This is the Accepted Manuscript (AM) version of the article and was originally published in Physics of Fluids; 28, 052001 (2016) and can be found online at:http://dx.doi.org/10.1063/1.4947597
This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing.
Citation Information
Xiaohua Wang, Rodolfo Fernandez, Nan Li, Hsien-Chih Hung, Anuradha Venkataraman, Richard Nordstrom and Andres H. La Rosa. (2016). Near-field acousto monitoring shear interactions inside a drop of fluid: The role of the zero-slip condition. Physics of Fluids, (28)5.