Abstract
It is known that turbulent frictional drag is reduced by adding polymer or surfactant into a turbulent flow. In the present study, the experimental analysis was performed in order to clarify temporal characteristics of turbulent fluctuation in surfactant solution flows. In various concentrations of surfactant solution, time series data of velocity fluctuations were measured by using a two-component LDV system at same Reynolds number. As a result of considering on temporal characteristics, it was found that the viscoelastic scale appears other than the scale of the turbulence vortex by adding the surfactant. The viscoelastic scale becomes longer as concentration levels increase and the turbulent vortex are disappeared obviously. Growing of the viscoelastic scale leads to the increase of frictional drag. It was also found that the small scale of turbulence vortex disappears near the wall region and buffer layer grows up.
