Laser-induced migration of oil particles suspended in a water matrix.
The thermoconvective flow induced in oil samples and oil-in-water emulsions by irradiation with a laser beam is studied experimentally. The samples are irradiated by He-Ne and CO2 lasers at different power levels. Time-resolved records of temperature and surface waves that propagate in a liquid surface are presented. In laser-heated emulsions the thermoconvective flow leads the dispersed oil droplets to the water-free surface where they agglomerate to form a floating oil layer. The reflected light beam is formed by a speckle pattern whose intensity and contrast show a spiking, quasi-periodic time variation. A theoretical model is proposed to explain this phenomenon.
Da Costa
German
G
Departamento de Física, Universidad Simón Bolivar, Caracas, Venezuela. german@usb.ve
Parra
Juan Enrique
JE
Mosqueda
Felix
F