Abstract
Sufficient knowledge of turbulence modification is indispensable to understand the turbulence structure and to develop a turbulence model in gas-liquid two-phase bubbly flow in vertical pipes. There is, however, little information on the interaction between shear-induced turbulence and bubbles in the near wall region, whereas many researches have been carried out on the turbulence properties in gas-liquid bubbly flow in a vertical pipe. In this study, we measured liquid velocity in the near wall region where the shear-induced turbulence is generated and interacts with bubbles. The measured result indicated that (1) bubbles increase the gradient of mean liquid velocity and therefore the shear-induced turbulence is enhanced in the near wall region, and (2) bubbles break up the developed large-scale shear-induced eddy and obstruct the transfer of turbulence energy from the near wall region to the core region.
