Three dimensional Shear-induced structure in drag reduction surfactant solutions
Thread-like micelles of cationic surfactant aggregate to SIS (Shear-induced structure), and the SISs are seems to attribute to drag reduction effect. In this study, we experimentally investigated drag-reducing flow using cationic surfactant solutions. The SISs were visualized in turbulent flow to elucidate the induced mechanism and role of a micelle structure and three dimensional SIS in drag reducing surfactant flow. The streamwise changes in the SISs and the drag reduction were measured and their relationship was discussed. In our experiments, the SISs were generated from a wall and had gel-like characteristics. The number and thickness of SISs increased downstream, and this increase was correlated with the streamwise increase in the drag reduction rate.