Experimental study of drag-reduction mechanism for a dilute surfactant solution flow
書誌事項
- 公開日
- 2008-02
- 権利情報
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- https://www.elsevier.com/tdm/userlicense/1.0/
- https://www.elsevier.com/legal/tdmrep-license
- DOI
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- 10.1016/j.ijheatmasstransfer.2007.04.048
- 公開者
- Elsevier BV
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説明
Abstract The quantitative characteristics of vortex structures and turbulent events in turbulent channel flows with and without drag reduction were investigated experimentally. Drag reducing aqueous solutions of CTAC (CTAC – cetyltrimethyl ammonium chloride) with concentration of 25 ppm and 75 ppm at 30 °C were tested. Particle image velocimetry (PIV) was used to measure the instantaneous velocity field in the streamwise–wall-normal plane of the flow. Through visualizing the instantaneous vector fields, contour maps of the swirling strength and instantaneous value of uv (u and v are the streamwise and wall-normal velocity fluctuations, respectively), the characteristic angle of vortex packets was quantified. It was shown that the drag-reducing CTAC additive reduced both the strength and frequency of turbulent bursts near the wall, and the characteristics of vortex structures and bursts were not only dependent on drag-reduction level but also on concentration of additive. From the quantified parameters characterizing turbulent events in a wall-bounded turbulent flow, it was obtained that fT was linearly proportional to the product of frequency and strength of turbulent events.
収録刊行物
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- International Journal of Heat and Mass Transfer
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International Journal of Heat and Mass Transfer 51 (3-4), 835-843, 2008-02
Elsevier BV