Abstract
We studied the mechanism of drag reduction due to the slip in Newtonian laminar flow through a rectangular micro channel. Fine fabrication was given to the test wall surface, and the surface was coated with PTFE for hydrophobic processing. Visualization experiment was carried out using a 5 x 0.5 mm micro channel. Shear rate is changed with the result of pressure loss measurement and the form of the air-liquid interface was visualized. A series of experiments showed that the air layer thickness decreased as the shear rate increased. Trethway et al (2004) showed that slip length rises dramatically as the air layer thickness increases. So the air layer thickness affects the drag reduction on textured surface.
