The characteristics of vortex structures and turbulent events of drag-reducing surfactant (CTAC) solution flows in a two-dimensional channel have been studied using particle image velocimetry (PIV) to measure the instantaneous velocity fields in a streamwise-wall-normal plane. Through visualizing the instantaneous velocity field, contour maps of the swirling strength and instantaneous value of uv, the characteristic angle of vortex packets was quantified, and it was shown that the drag-reducing CTAC additive reduced both the strength and frequency of turbulent bursts near the wall, and that the characteristics of vortex structures and bursts were not only dependent on drag-reduction level but also on concentration of additive. Based on the quantified parameters characterizing turbulent events in a wall-bounded turbulent flow, a model of turbulent contribution to the friction factor, f T, was proposed. It was obtained that fT was linearly proportional to the product of frequency and strength of turbulent events.
|出版ステータス||Published - 2004 1月 1|
|イベント||Proceedings of the ASME Heat Transfer/Fluids Engineering Summer Conference 2004, HT/FED 2004 - Charlotte, NC, United States|
継続期間: 2004 7月 11 → 2004 7月 15
|Other||Proceedings of the ASME Heat Transfer/Fluids Engineering Summer Conference 2004, HT/FED 2004|
|Period||04/7/11 → 04/7/15|
ASJC Scopus subject areas