This research aims to advance fundamental understanding of granular segregation at the particle level and enhance predictive modeling of size and/or density segregation across various flow configurations.

The first result is how large and small particles migrate at the particle scale, hinting at completely different physics (Jing et al., 2017). Based on this microscopic understanding, a bottom-up theoretical model is developed to describe the net force driving segregation in terms of particle properties (size ratio, density ratio) and local flow conditions (pressure, shear rate, and their gradients), which unifies two major driving mechanisms of segregation – gravity and shear-induced gradients (Jing et al., 2021). The force model is shown to accurately predict the segregation direction, over a wide range of conditions, in various flow configurations (Jing et al., 2020; Jing et al., 2021). Recently, our model is extended to provide closure relations for segregation modeling in continuum granular flow theories (Duan et al., 2022).

The findings are expected to serve as the backbone of radically new methods for predicting and even controlling segregation in industrial and geophysical applications.

  1. Jing, L., Kwok, C. Y., & Leung, Y. F. (2017). Micromechanical origin of particle size segregation. Physical Review Letters, 118(11), 118001. https://doi.org/10.1103/PhysRevLett.118.118001
  2. Jing, L., Ottino, J. M., Lueptow, R. M., & Umbanhowar, P. B. (2021). A unified description of gravity- and kinematics-induced segregation forces in dense granular flows. Journal of Fluid Mechanics, 925, A29. https://doi.org/10.1017/jfm.2021.688
  3. Jing, L., Ottino, J. M., Lueptow, R. M., & Umbanhowar, P. B. (2020). Rising and sinking intruders in dense granular flows. Physical Review Research, 2(2), 022069. https://doi.org/10.1103/PhysRevResearch.2.022069
  4. Duan, Y., Jing, L., Umbanhowar, P. B., Ottino, J. M., & Lueptow, R. M. (2022). Segregation forces in dense granular flows: Closing the gap between single intruders and mixtures. Journal of Fluid Mechanics, 935, R1. https://doi.org/10.1017/jfm.2022.12