Viscoelastic Drag Forces and Crossover from No-Slip to Slip Boundary Conditions for Flow near Air-Water Interfaces.
Phys Rev Lett
; 118(8): 084501, 2017 Feb 24.
Article
en En
| MEDLINE
| ID: mdl-28282178
ABSTRACT
The "free" water surface is generally prone to contamination with surface impurities, be they surfactants, particles, or other surface active agents. The presence of such impurities can modify flow near such interfaces in a drastic manner. Here we show that vibrating a small sphere mounted on an atomic force microscope cantilever near a gas bubble immersed in water is an excellent probe of surface contamination. Both viscous and elastic forces are exerted by an air-water interface on the vibrating sphere even when very low doses of contaminants are present. The viscous drag forces show a crossover from no-slip to slip boundary conditions while the elastic forces show a nontrivial variation as the vibration frequency changes. We provide a simple model to rationalize these results and propose a simple way of evaluating the concentration of such surface impurities.
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1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Año:
2017
Tipo del documento:
Article
País de afiliación:
Francia