水平チャネル内流れにおける投影ボイド率変化と局所せん断応力変動の比較

抄録

We have succeeded in grasping changes in shear stress by using a Laser Doppler Shear Stress Sensor to directly measure the time fluctuation of shear stress in turbulent flow. A decrease in stress is confirmed in the two-phase flow. However, it has not been investigated what kind of bubbles will affect the stress. In this research, we investigated the influence of bubbles on wall shear stress by measuring shear stress using direct measurement method of bubble flow and visualizing bubbles covering sensor surface. At the void fraction α=1.0, it was found that the shear stress did not decrease but rather increased at 5 m/sec, 7 m/sec. It was found that to reduce the shear stress, it is necessary to cover the area of more than 5% with bubbles in the local area.