1999/01/31 by W. Losert, D. G. W. Cooper, J. Delour +2 · 4 citations
Engineering · Physics and Astronomy · #Distribution (mathematics) #Dust and Plasma Wave Phenomena #Excited state #Exponential function #Gaussian #Granular flow and fluidized beds #Kinetic energy #Particle (ecology) #Particle Dynamics in Fluid Flows #Particle velocity #Range (aeronautics) #Thermal velocity #cond-mat.stat-mech
paper · pdf · doi:10.1063/1.166442
27 pages, 13 figures, to appear in Chaos, September 99, revised 3 figures and text
arxiv created 1999/06/29 · openalex publication_date 1999/09/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We present an experimental study of velocity statistics for a partial layer of inelastic colliding beads driven by a vertically oscillating boundary. Over a wide range of parameters (accelerations 3-8 times the gravitational acceleration), the probability distribution P(v) deviates measurably from a Gaussian for the two horizontal velocity components. It can be described by P(v) approximately exp(-mid R:v/v(c)mid R:(1.5)), in agreement with a recent theory. The characteristic velocity v(c) is proportional to the peak velocity of the boundary. The granular temperature, defined as the mean square particle velocity, varies with particle density and exhibits a maximum at intermediate densities. On the other hand, for free cooling in the absence of excitation, we find an exponential velocity distribution. Finally, we examine the sharing of energy between particles of different mass. The more massive particles are found to have greater kinetic energy. (c) 1999 American Institute of Physics.