抄録
A measurement method of local instantaneous velocity gradients in turbulent flows are required to evaluate turbulence kinetic energy (TKE) budget. Spatiotemporal Filter Velocimetry (SFV) is therefore applied to evaluation of TKE budget by coupling with a molecular tagging method using photobleaching reaction. Measurements are carried out not only for single-phase turbulent flow but also for bubbly flows with two different bubble diameters to examine effects of bubble diameter on the velocity distribution and TKE budget. As a result, the following conclusions are obtained: (1) Effect of bubble diameter on the distribution of axial mean velocity is weak under the fixed void distribution and the fixed interaction forces between the phases. (2) Effect of bubble diameter on TKE budget is not so large in the bubbly flows whereas the presence of bubbles tend to reduce the magnitudes of the production and diffusion rates.
