ABSTRACT
Cohesive-frictional and rough powders show peculiar flow behavior due to the fact that several contact forces/torques are equally important. Friction, rollingresistance, and contact-adhesion are active at the same time and lead to macroscopic cohesion and macroscopic friction that is not proportional to the microscopic contact parameters. Besides many experiments, Molecular Dynamics (MD) or Discrete Element Models (DEM), which solve the equations of motion for all particles in a system, are used to understand these granular media. While experiments and continuum theory deal with macroscopic material parameters, for the particle simulations, the (microscopic) contact forces are the only physical laws that have to be defined beforehand (Luding 1998; Bartels et al. 2005; Dintwa et al. 2005; Luding 2006). The present simulation results are based on the contact model in the paper by Luding (Luding 2006; Luding 2008).
