Multi-camera PIV imaging in two-phase flow for improved dispersed-phase concentration and velocity calculation

Sediment transport from a mobile bed is characterized by large spatial gradients in sediment concentration embedded within a strongly coupled turbulent boundary layer. One of the fundamental open questions of study is how these particle-laden flows modulate the turbulence and the effective stress that is communicated to the outer flow and bed. In the current work, we are interested in advancing quantitative imaging to provide simultaneous high-resolution measures of both phases (sediment and water). In the majority of these conditions, the sediment particles are typically 1-2 orders of magnitude larger than the tracers, which renders the utilization of the most recent developments in tracer particle tracking techniques ineffective (e.g. shake-the-box, MART), as they rely on the assumption of a prescribed simple particle image model. The current work is an extension of prior efforts developing a multi-camera imaging method for extending concentration measurement, incorporating the temporal information for the purpose of resolving the instantaneous velocity of both the dispersed phase and the carrier tracer particles. Finally, the proposed method is employed to an oscillating sheet flow experiment and the phase averaged sediment concentration and flux results are presented.