Turbulence structure of liquid-solid two-phase channel flow (1st report, measurements of two-phase flow by DPIV)

The interactions between dispersed particles and fluid turbulence have been investigated in a fully-developed water channel. Particle velocities and fluid velocities in the presence of 340 μm and 500 μm glass beads, and 420 μm cellulose particles were measured by digital particle image velocimetry (DPIV). These particles were comparable to or slightly greater than the Kolmogorov lengthscale of the flow (320 μm). Although there was no apparent modification to the mean flow, an increase in turbulence intensities was greater in the streamwise than in the transverse direction, due to an increase in the turbulence energy in the streamwise direction. Particle concentration fluctuation increased the turbulence energy in the low-wave-number region, which means that the turbulence was modified by preferentially concentrated particles.