チャネル乱流における気泡径の壁面摩擦抵抗低減効果へ及ぼす影響(混相流,一般講演)

概要

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The phenomenon of the drag reduction effect with microbubble has been studied experimentally. We revealed the drag reduction effect by using large bubble of millimeter and medium bubble of sub-millimeter. We have approached by wall shear stress measurement and flow visualization by using PTV. In both bubble flows, the experiments have been carried out with the Reynolds number ranging from 10,000 to 50,000 and void fraction up to 0.04. In Re=20,000, skin friction was decreased while the reduction effect was not observed in large bubble flow. When drag reduction effect was observed, a negative correlation on u' v' was weakened significantly and the ejection and sweep event were reduced by bubble injection and Reynolds stress was decreased.
日本流体力学会の論文
2007-08-06