Mechanics and numerical simulations of Dry Granular Flows driven by gravity

The gravitational granular flows (e.g. debris flows or snow avalanches) are catastrophic and destructive phenomena affecting many areas in the world, and especially the mountain areas of Europe. Proper design criteria are required in order to improve protection structures and prevention strategies. Due to their complex nature, these phenomena present many aspects still unsolved in the research field. This research addresses some aspects of the mechanics of dry granular flows: a 1D depth integrated model has been developed, based on a two phase approach. The system of equations consists of three partial differential equations, derived from the mass balances for the solid and fluid phase and from the momentum balance for the solid phase, and two rheological relations determined through experimental tests and particle numerical simulations. The experimental investigation hes been conducted in a laboratory channel, by recording through high speed cameras the motion of polystyrene spherical particles. Within this research, it has been developed an ad hoc optical method to analyze and process the images recorded, with the aim of defining the main flow characteristics. From a numerical point of view, a path conservative finite volume scheme has been adopted to solve the system of equations previously described: the numerical solution is compared to the experimental results for different configurations, in order to verify the effectiveness of the mode