Granular flow in rotating drums through simulations adopting a continuum constitutive equation

The need for a detailed description of dense granular flows arises in several practical applications. A continuum approach, where the solid phase is treated as a continuum, is suitable for large-scale flow modeling, as in the case of an industrial drum containing billions of particles. In this work, we present three-dimensional finite volume simulations of dense granular flow inside a rotating cylinder, adopting the viscoplastic Jop-Forterre-Pouliquen constitutive model for the granular medium stress tensor [Jop et al., "A constitutive law for dense granular flows,"Nature 441, 727-730 (2006)], the so-called μ(I)-rheology. The results obtained from our simulations are also compared with several experimental results available in the literature. Qualitative and even quantitative agreement with data is found: we are able to reproduce the experimentally observed flow regime sequence in rotating drums, ranging from rolling to centrifuging, and to predict flow fields of interest within the granular phase in agreement with experimental results, not only on the drum center but also along the axial direction. This approach characterizes a wide variety of regimes by changing both physical and geometrical parameters and gives details on several flow quantities difficult to be accessed through experiments, but of practical interest.