0901 鉛直ダクト内乱流の乱れエネルギ収支に及ぼす気泡の影響(OS9-1 先端的熱流体計測法,オーガナイズドセッション)

概要

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Since the conservation equation of turbulence kinetic energy (TKE) involves correlations among local instantaneous gradients of fluctuating velocities, it is indispensable to measure the velocity gradients as well as the velocity components. The authors developed a molecular tagging method using photobleaching (PB-MTV), which can measure not only velocity but also its gradient by making use of the translation and deformation of a tag. In this study, we applied the PB-MTV to turbulent bubbly flows in a square duct. The experimental results indicate that position of turbulence transition between viscous sub-layer and log region shifts toward the wall by the presence of bubbles. The presence of bubbles increases not only the production rate but also the dissipation rate of TKE. The enhancements in the production and the dissipation rates are well correlated with the local void fraction.
社団法人日本機械学会の論文
2009-11-06