Abstract
In the first report, the authors showed a new concept to reduce turbulent frictional drag by injecting high-viscosity fluid into boundary layer. The experimental result showed a substantial reduction of shear stress by injecting sugar sirup which was used as high-vescosity fluid and water from the double slits.
In this report, the experiment of water/sugar sirup injection was done in many conditions. The injected sugar sirup looked white that was because of a large difference in index of refraction between water and sugar sirup. So Laser Doppler Velocimeter could not be used for measurement of velocity distribution. In this report, the velocity distribution was measured by cross-correlation method using a pair of hot film anemometers. The velocity gradient became less at the vicinity of the wall when the water/sugar sirup was injected. It confirmed the hypothesis of drag reduction shown in the first report. A finite difference computation was also made for different viscosity layers in boundary layer.
