Are
Temperature and other Thermodynamics Variables efficient Concepts for
describing Granular Gases and/or Flows ?
Abstract: Granular flows and
vibro-fluidised granular gases have been extensively studied recently; most of
the theoretical analyses and the experimental descriptions use temperature and
other thermodynamics concepts. However, taking the very simple case of a
vibro-fluidised gas made of identical particles, we show the lack of efficiency
of such concepts for the understanding of the physics of such systems. This
results from both (i) the fact that the vibrator does not transmit the same
amount of energy to each particle, but
an amount which depends on its mass and/or its size and (ii) from the fact that
it is a strongly dissipative medium. We conclude that most experimental device
works rather as velostat as a
thermostat.
Pacs # : 5.40 ; 45.70 ; 62.20 ; 83.70.Fn
poudres
& grains 13 (2),
20-26 ( Avril 2002)