Published In

Physics of Fluids

Document Type

Article

Publication Date

10-2016

Subjects

Capillarity -- Research, Microfluidics, Fluid dynamics

Abstract

Large droplets and puddles jump spontaneously from sufficiently hydrophobicsurfaces during routine drop tower tests. The simple low-cost passive mechanism can in turn be used as an experimental device to investigate dynamic droplet phenomena for drops up to 104 times larger than their normal terrestrial counterparts. We provide and/or confirm quick and qualitative design guides for such “drop shooters” as employed in drop tower tests including relationships to predict droplet ejection durations and velocities as functions of drop volume, surface texture, surface contour, wettability pattern, and fluid properties including contact angle. The latter is determined via profile image comparisons with numerical equilibrium interface computations. Water drop volumes of 0.04–400 ml at ejection speeds of −0.007–0.12 m/s are demonstrated herein. A sample application of the drop jump method is made to the classic problem of low-gravity phase change heat transfer for large impinging drops. Many other candidate problems might be identified by the reader.

Description

This is the publisher's final pdf. Copyright (2016) AIP. Version of record can be found at https://dx.doi.org/10.1063/1.4963686

DOI

10.1063/1.4963686

Persistent Identifier

http://archives.pdx.edu/ds/psu/19397

Available for download on Sunday, October 01, 2017

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