Methods for the physical measurement of collisional particle flows

Particle image velocimetry (PIV) and particle tracking velocimetry (PTV) are used in this paper to test their ability in measuring kinematic properties of granular flows, such velocity fluctuations and granular temperature. A small inclined chute geometry was used here to reproduce flows encompassing different flow regimes. An experimental investigation of a dry free-surface flow composed of almost spherical monodisperse ceramic beads is presented. The two image velocimetry techniques are directly applied to images captured in a region of the flow where an apparent uniform steady regime was observed. Our results shows that PTV is capable of measuring the movement of individual particles resulting in estimations of granular temperature that can be compared with other studies. In contrast, PIV tends to damp the magnitude of the random component of the velocities, which in turn produces lower values of granular temperature.