On continuum modeling using kinetic–frictional models in high shear granulation

In this short communication we explain and demonstrate why extreme caution has to be taken when applying conventional kinetic-frictional closures to continuum modeling of high shear granulation (HSG). By conventional models, we refer to closure laws where the kinetic and frictional stresses are summed up in order to get the total stress field. In a simple dense sheared system of a Couette shear cell, we study how the lack of scale separation affects the model predictions, both quantitatively and qualitatively. We show here that the spatial resolution has a significant effect on the magnitude of the kinetic and frictional contributions to the solid phase stresses. With this new investigation and previous studies of HSG it is concluded that conventional kinetic-frictional models are inadequate for continuum modeling of HSG.