Continuum modeling of shear dilatancy-induced secondary flow in granular media

This study explores the transient evolution of dilation-driven secondary flows in a dense, slowly sheared granular medium using the non-local continuum model of Dsouza and Nott [1]. In earlier studies, DEM simulations have shown that shear-induced dilatancy, coupled with gravity, sustains a system-spanning secondary vortex in a plane Couette setup with a free surface. We impose a fixed top boundary and a prescribed mean volume fraction to simplify computations. The model captures the emergence of transient, dilation-driven secondary vortices, mirroring qualitative features of the simulations. The magnitude of the secondary velocity is smaller than that in DEM simulations, reflecting suppression of expansion by the fixed boundary. These findings validate the model’s robustness and establish a foundation for future studies incorporating free-surface conditions.