Abstract
The skin friction reduction improves the transport efficiency of ships because the skin friction acting on large ships occupies the majority of the total drag. Recently, a technique to reduce the skin friction by injecting microbubbles into the turbulent boundary layer have been investigated for application to ships. However, the mechanism on its reduction is still not fully understood yet. In this study, the turbulence structure in the turbulent boundary layer with microbubbles was investigated experimentally by using the PIV/LIF measurement for the horizontal channel flow. In addition, a new system based on the combination of PIV, LIF and IST is proposed in order to obtain the distribution of microbubbles.
