2322 希薄界面活性剤水溶液の管内流遷移(S42-5 複雑流体の流動現象(5),S42 複雑流体の流動現象)  [in Japanese] 2322 Laminar-Turbulent Transition in Pipe Flow of Dilute Surfactant-Water Solutions  [in Japanese]

This paper describes the effect of drag reducing surfactant (C_<14>TABr) additives on the laminar-turbulent transition in pipe flow. The experiment was carried out using the glass tube of 5.02mm in diameter and 2712mm in length. The transition process depending on the surfactant concentration was observed by means of high-speed video photography. Within the Reynolds number ranging from 2000 to 3000, a temporary rapid increase in the friction factor appeared although the flow was quasi-laminar. In a surfactant concentration that exceeds 230 ppm, a turbulent transition happened gradually and vaguely, not drastically as the Reynolds number increased.