Dynamics of quasi-2D dissipative granular gas is studied in microgravity condition (of the order of 10E-4 g) in the limit of Knudsen regime. The gas, made of 4 spheres, is confined in a square cell enforced to follow linear sinusoidal vibration in ten different vibration modes. The trajectory of one of the particles is followed for 2 hours, and is reconstructed from video data by particle tracking. From statistical analysis, we find that (i) loss due to wall friction is small, (ii) trajectory looks ergodic in space, and (iii) distribution p(v) of speed follows an exponential distribution, i.e., p(ny) about exp[-ny/(ny(x(0),y(0))], with ny(x(0),y(0)) being a characteristic velocity along a direction parallel (y) or perpendicular (x) to vibration direction. This law deviates strongly from the Boltzmann distribution of speed in molecular gas. Comparisons of this result with previous measurements in earth environment, and what was found in 3D cell (Falcon et al., Europhys. Lett 74:830, 2006) performed in environment of about plus or minus 5 x 10E-2 g are given.
Velocity distribution of vibration-driven granular gas in Knudsen regime in microgravity
Geschwindigkeitsverteilung einer Schwingungs-induzierten Bewegung von granularem Gas im Knudsen-Regime unter Schwerelosigkeit
Microgravity Science and Technology ; 20 , 2 ; 73-80
2008
8 Seiten, 7 Bilder, 1 Tabelle, 16 Quellen
Article (Journal)
English
Microgravity experiments on granular materials
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