Theses videos show the collapse of fixed width granular column:
- on the first, aspect ratio a=10, with water,
- on the second, aspect ratio a=7, in a more viscous fluid.
Grains diameter = 10-3 m, grains density = 2.6. The viscous fluid has a 1000 higher viscosity than water.
The color levels indicate the particles and fluid velocities (red for the higher velocities, blue for the lowest ones).
Collapse of granular column. Aspect ratio a=10, with water. © IRSN
Collapse of granular column. Aspect ratio a=7, in a more viscous fluid. © IRSN