抄録
The flow around a circular cylinder in surfactant solution was investigated experimentally by measuring the pressure distribution. Test surfactant solutions were Ethoquad O/12 at concentrations of 50, 100 and 200 ppm, and sodium salicylate was added as counterion. It was clarified that the pressure coefficient behind separation point around a circular cylinder in surfactant solution was larger than that in tap water, and the separation angle was increased with increasing the concentration of surfactant solutions. The drag coefficient of a circular cylinder in surfactant solution was smaller than that in tap water in the Reynolds number range of 10000 < Re < 50000, and no drag reduction occurred at Re=6000. The drag reduction ratio was increased with increasing the concentrations of surfactant solutions. The maximum drag reduction ratio was about 35%.
