Need for improved settling and tracer flux models for bidisperse suspensions

Determine whether the settling flux and tracer flux formulations used in the bidisperse equilibrium model—adapted from bidensity models by changing only species-dependent diameters—require more accurate, size-aware modeling to capture bidisperse effects; and evaluate the impact of revised flux laws on the model’s qualitative predictions.

Background

The shear-induced migration term was adapted to handle different particle sizes, but the settling and tracer fluxes were largely retained from bidensity formulations with only diameter substitutions.

The authors note that, unlike the bidensity case, the tracer fluxes for two sizes do not cancel, and they explicitly state uncertainty about the need for more accurate modeling of these two fluxes.