Eddies, mixing and heat transfer in dense granular flows

Abstract

Abstract. We investigate the ability of dense granular flows to transfer heat while flowing. Using discrete element simulations, we show that large correlated motions of grains develop in dense granular sheared layer, and lead to a strong heat transfer across streamlines. This process is similar to the convection induced by eddies in turbulent flows. However, granular eddies do not result from visco-inertial instability, but from the steric exclusion of closely packed grains. As a result, they seem to develop even at very low shear rates, which could have a significant practical interest. Beyond their different natures, classical turbulence and granular turbulence face similar challenges, and it is hoped that research in these two fields can benefit from each other.