Journal of Fluid Mechanics



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Direct measurement of slip velocities using three-dimensional total internal reflection velocimetry


PETER HUANG a1, JEFFREY S. GUASTO a1 and KENNETH S. BREUER a1
a1 Division of Engineering, Brown University, Providence, RI 02915, USA

Article author query
huang p   [Google Scholar] 
guasto js   [Google Scholar] 
breuer ks   [Google Scholar] 
 

Abstract

The existence and magnitude of slip velocities between deionized water and a smooth glass surface is studied experimentally. Sub-micron fluorescent particles are suspended in water and imaged using total internal reflection velocimetry (TIRV). For water flowing over a hydrophilic surface, the measurements are in agreement with previous experiments and indicate that slip, if present, is minimal at low shear rates, but increases slightly as the shear rate increases. Surface hydrophobicity is observed to induce a small slip velocity, with the slip length reaching a maximum of 96 nm at a shear rate of 1800$\,{\rm s}^{-1}$. Issues associated with the experimental technique and the interpretation of results are also discussed.

(Received September 19 2005)
(Revised May 5 2006)



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