Instability of Particle-Laden Flow in a Spatially-Periodic Channel

Laboratory experiments are conducted for suspension flows in a channel with a geometry that is textured with cylindrical obstructions placed periodically in the streamwise direction. In the absence of particles, the pure flow becomes convectively unstable at a critical Reynolds number of approximately 130 and exhibits a supercritical bifurcation to a secondary flow in the form of non-turbulent 2D wave packets. We examine the effect of adding inertial particles on the critical Re and the onset of instability. Moreover, we describe novel particle accumulation behaviors that arise in the presence of the secondary flow. The experimental results are compared to direct numerical simulations.

Supported by NSF grants 22-30893 and 22-30894.