Maximum drag reduction and scale up of surfactant solution

Turbulent drag reducing characteristics of CTAC/NaSal aqueous solution (CTAC had same mass concentration with NaSal.) were investigated in a two-dimensional channel of 30 mm height and 375 mm width, which was made of transparent acrylic resin. The measured drag reduction data were scaled up by using Hoyt's scaling method and were compared with other reported drag reduction data for different channel sizes. It could be concluded that both the critical temperature and critical Reynolds number at which turbulent drag reduction of surfactant solution occurred increased with concentration. There was a maximum drag-reduction about 60% for the measured CTAC/NaSal solutions. The Hoyt's scale-up method correlated well the experimental data for different channel heights when the SIS (shearing induced structure) was established very well in surfactant solutions.