The speed at which a dune migrates depends on its size; smaller dunes move faster than larger ones. That speed differential implies that small dunes should frequently collide into and Keep reading
Tag: granular flow
The Sand Sea’s End
The northern extent of Africa’s Namib Sand Sea ends where the reddish dunes meet the Kuiseb River and the hard, rocky land on its other side. Within the sand sea, Keep reading
Martian Landslides
Sometimes there are advantages to studying planetary physics beyond Earth. Mars does not have plate tectonics, vegetation, or the level of erosion we do, allowing geological features like those left Keep reading
Giving Chocolate that Smooth Finish
Anyone who’s tried to make chocolate confections at home can tell you that achieving that perfect smooth consistency isn’t easy. It was only after Rodolphe Lindt invented the process of Keep reading
Granular Instabilities
Granular mixtures show surprising similarities to fluids, even though their underlying physics differ. The latest example of this is a Rayleigh-Taylor-like instability that occurs when heavy particles sit atop lighter Keep reading
Recreating Pyroclastic Flow
One of the deadliest features of some volcanic eruptions is the pyroclastic flow, a current of hot gas and volcanic ash capable of moving hundreds of kilometers an hour and Keep reading
Inside Avalanches
Avalanches have traditionally been difficult to model and predict because of their complex nature. In the case of a slab avalanche, the sort often triggered by a lone skier or Keep reading
Flowing Flowers
Granular mixtures with particles of different sizes will often segregate themselves when flowing. In this half-filled rotating drum large red particles and smaller white ones create a stable petal-like pattern. Keep reading
Grain Networks
Granular materials are complicated beasts. When packed, forces between grains create a network (above) that shifts as force is applied. And, while grains can stick and resist that force, push Keep reading
Sandy Wrinkles
Water flowing back and forth over sand quickly forms a field of dune-like wrinkles. On the upstream side, the flow is a little faster, and it picks up grains of Keep reading