Numerical simulation of the effects of particle density and size on particle distribution in a laboratory-scale curved open-channel flow

Understanding the distribution patterns of particles within a curved open-channel flow is crucial for designing water intakes, assessing and restoring habitats, regulating sediment, and more. This study examined how particle density and size influence the distribution of particles in a curved open-channel flow, based on Stereoscopic Particle Image Velocimetry and Discrete Phase Model. Numerical simulations demonstrate that the flow within the bend shows significant mainstream deviation and secondary circulation, which are consistent with the measured results. The research indicates that particle density and size have a significant impact on particle migration trajectories and aggregation in the bend. Particles with low density tend to remain near the central region or upper layers of the flow, whereas those with higher density and larger diameter, owing to their greater inertia and gravitational settling, are more likely to accumulate near the outer bank and bottom layers. The interplay between inertial forces and secondary flow structures gives rise to distinct horizontal and vertical distribution patterns. Considering particle size distribution, particles with larger Stokes numbers tend to concentrate in the outer region of the bend, particularly on the outer side of the 90° ∼ 180° cross-section. These results contribute to a deeper understanding of particle transport behavior in curved channels and offer support for the modeling of particle-laden flows.