(208a) Designing Non-Segregating Granular Mixtures for Free Surface Flows

Granular materials tend to segregate due to differences in particle size and density. However, for bidisperse mixtures of large/heavy and small/light spherical particles, the effects of these differences can be balanced for specific combinations of particle size ratio, density ratio, and mixture concentration so that the particles remain mixed. Using discrete element method (DEM) simulations of a quasi-two-dimensional rotating tumbler we show that segregation is minimized for initially well-mixed particle mixtures near the equilibrium conditions. More significantly, we show that initially segregated particles mix and remain mixed. Overall, our results demonstrate that in free-surface flows, non-segregating granular mixtures can be realized through principled design. Funded by NSF Grant CBET-1929265.