Movies:

• Spontaneous organization of vortex paterns is observed when anisotropic granular materials (rods) are vibrated in a container. In the movie, rods are initially placed randomly, and are observed align vertically upon vibration, and then undergo vortex motion. We show that the direction of motion of the rods is always in the direction of inclination of the rods. Click for more information.
• Novel clusters are observed to self-assemble when dipolar particles (magnetized particles) are vibrated inside a container. The clusters are observed to form, when the vibration amplitude is lowered below a critical value. The nature of the clusters depends on the rate at which the amplitude is lowered. An example of the evolution of the cluster is shown in the movie. The cluster is observed to grow and move to the boundary due to depletion forces. The granular temperature of the particles in the cluster is observed to lower than that of the particles in the surrounding gas, showing a breakdown of equipartition of energy. Click for more information.
• Shocks are observed in granular materials draining from an orifice at high flow rates. A hydraulic jump like feature is observed at the surface. A movie is shown. The width of the viewing region is 10 cm and the orifice is 2.5 cm wide. The surface is observed to deviate strongly from the approximately linear profile observed at low flow rates.
  A close up movie of the granular hydraulic jump. Click for more info.
• Wave patterns are observed when spherical particles are vibrated in a container. In the movie, the patterns formed by 3 mm steel ball bearings rolling on an inclined surface is shown using a high speed camera. Click for more info.
• Movies of time-dependent surface wave patterns observed in a fluid inside a stadium shaped container:
  • 72 seconds at 3 frames per second (0.9 MB)

  • 370 seconds at 3 frames per second (6.7 MB)
  Aperiodic oscillation between spatially ordered and disordered patterns is observed (driving frequency = 55 Hz). Click for more info.

Featured in the TV program ARCHIMEDE, broadcast on the ARTE French and German cultural network, January 14, 2003.

Last updated January 28, 2003.