Granular hydrodynamics and density wave regimes in a vertical chute experiment

We report experiments on grains falling in a bidimensional vertical column. We identify a steady flow regime and, for narrow openings, a regime of den sity waves. The density, velocity and temperature fields are measured and c ompared with the prediction of a granular hydrodynamics theory. We find a g ood qualitative agreement for weakly dissipative particles but for the more dissipative ones, we evidence a new regime of momentum and energy transpor t characterized by a clogging dynamics.