(276f) Granular Segregation Forces

Segregation in granular flows occurs due to the combined effects of gravity and shear. Recent studies successfully characterized the gravity-induced segregation force in a well-mixed size-bidisperse granular mixture under uniform shear using a buoyancy-like pressure gradient term combined with a semi-empirical concentration-dependent function. However, a generalized force model is still lacking for non-uninform shear flows with locally varying shear rate and mixture concentration. Here we explore the mixture segregation force, particularly the shear-induced component, using DEM simulations of controlled-velocity flows where the shear and concentration profiles are varied. The local segregation force is quantified using a modified virtual-spring-based 'force meter' technique. Combining a previously established single intruder segregation force model that includes both pressure gradient and shear-rate gradient terms with the semi-empirical concentration dependent function produces a framework that predicts the locally varying segregation force in non-uninform shear flows of size-bidisperse particle mixtures over a range of concentrations, pressures, shear rates, and particle size ratios.

*Funded by NSF Grant no. CBET-1929265.