Simultaneous measurement of fluid and dispersed phases in a particle-ladenturbulent channel flow with the aid of 3-D PTV

Three-dimensional high-definition particle tracking velocimetry is successf ully applied to simultaneous measurement of fluid and dispersed phases in a vertical turbulent water channel flow. Turbulence statistics are substanti ally modified by the solid particles having a diameter of twice the Kolmogo rov length scale. The streamwise turbulence intensity of the fluid phase is significantly increased in the channel, whilst it is unchanged at y(+) < 2 0. In contrast, the wall-normal and spanwise components are increased in th e whole cross-section. In the center of the channel, the wake behind a soli d particle has almost the same streamwise length as that around a sphere in the uniform flow, and particles tend to align in the streamwise direction as they flow downstream. The quadrant analysis shows that the solid particl es are densely distributed along the low-speed streaks, especially beneath the ejection event. The difference in traceability of particles to the ejec tion and sweep events should contribute to the particle agglomeration.