気泡を含む水平チャネル乱流の壁面摩擦抵抗 : 気液界面挙動と局所壁面せん断応力の同期計測実験(流体工学,流体機械)

概要

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Skin frictional drag of bubbly two-phase mixture in a horizontal turbulent channel is investigated experimentally using a shear stress sensor and a high-speed video camera. We choose non-micro bubbles having a size of 1 to 10mm intentionally to confirm that the drag reduction still works with relatively large bubbles to the channel height. The measurement results have shown that the drag reduction realized in case of a void fraction higher than a critical value that depends on liquid flow velocity. Also, significant bubble size dependence was found in the region near bubble injector. A synchronized measurement of local shear stress and interfacial structure has newly shown that the instantaneous friction factor decreased in rear part of individual bubble.
2005-06-25