Effect of base roughness on flow behaviour and size segregation in dry granular flows

Three bases with increasing roughness were designed by adjusting the geometric relationships of particles bonded to the base, to study the roughness effect on flow behaviour and size segregation in bidisperse granular chute flows. In light of limited research on accurate tracking of different particles in bidisperse granular flows, particle tracking velocimetry, which allows tracking of large and small particles down to the pixel level, was used to measure the velocity and displacement of large and small particles separately. Experimental results show that when the critical inclination theta(c) increases from 31 center dot 9 degrees to 36 center dot 1 degrees, the mixing point of the large and small particles decreases from 67 to 39 cm. Moreover, the overall flow is suppressed in the stream-wise direction and promoted in the depth-wise direction as the base roughness increases.