Time-Dependent Dual-Phase Measurements in a Particle-Laden Turbulent Boundary Layer

The transport of large and heavy solid particles by gaseous wall-bounded turbulent flows is a phenomenon relevant to a wide range of both natural and industrial processes. This work outlines an experimental framework developed to investigate the coupled interactions between the particle and carrier (air) phases. Experiments were conducted in a turbulent boundary layer developing over a 2.44 m long bed of large, spherical soda-lime particles with diameters in the range of 300-425 microns. Measurements of particles in various stages of mobilization were acquired in an open-return boundary layer wind tunnel at a nominal free-stream velocity corresponding to a friction Reynolds number, Re_τ, of approximately 1800. Simultaneous measurements of the carrier and particle phases were carried out at a sampling frequency of 2 kHz using a mosaiced camera arrangement, with one camera focused on the near-wall region and the other on the outer flow. The carrier phase was resolved using a conventional PIV algorithm after masking the particle phase. The particle phase was isolated via a k-means clustering approach, and its motion was quantified using a particle tracking algorithm. Demonstrative results are presented to highlight the capability of this framework to capture the coupled particle–fluid dynamics.