Experiments and simulations of a gravitational granular flow instability.

An instability is observed as a layer of dense granular material positioned above a layer of air falls in a gravitational field [Phys. Rev. Lett. 99, 048001 (2007)]. A characteristic pattern of fingers emerges along the interface defined by the grains, and a transient coarsening of the structure is caused by a coalescence of neighboring fingers. The… CONTINUE READING