(414e) Experimental Study of Particle Density Segregation in Granular Shear Flow

It is well known that as a granular material is sheared, the bed dilates and heavier particles move perpendicular to the mean flow. Our previous computational study established a connection between particle density segregation, solid volume fraction and the so call inertia number. In this work, we perform experiments aimed at physically realizing the predictions of our proposed theory (and computational results). Specifically, we have constructed an experimental annular Couette cell that has a moving lower lid and fixed inner, outer, and top wall. With this device we can control the solid volume fraction by applying either a constant volume or constant pressure condition at the top wall as well as the global shear rate via modification of the bottom lid rotation rate. We perform trials that follow the segregation velocity of heavy steel tracer particles as they move within a background media of either acetate or glass. Similar to our previous computational and theoretical results, we find a saturated segregation velocity regime and a direct connection between segregation velocity and solid volume fraction/inertia number.