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On the relevance of “molecular chaos” for granular flows
Author(s) -
Luding Stefan
Publication year - 2000
Publication title -
zamm ‐ journal of applied mathematics and mechanics / zeitschrift für angewandte mathematik und mechanik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.449
H-Index - 51
eISSN - 1521-4001
pISSN - 0044-2267
DOI - 10.1002/zamm.20000801303
Subject(s) - dissipative system , formalism (music) , dissipation , statistical physics , uncorrelated , classical mechanics , physics , chaos (operating system) , convection , kinetic energy , universality (dynamical systems) , molecular dynamics , mechanics , mathematics , computer science , quantum mechanics , statistics , art , musical , computer security , visual arts
Abstract With numerical simulations of dissipative, spherical particles the assumption is tested, that the velocities and the positions of colliding particles are uncorrelated (“molecular chaos”). This assumption is a basic ingredient of all theoretical approaches based on a kinetic theory or a pseudo‐Liouville operator formalism. The numerical model is an event‐driven method for the simulation of rigid spherical particles in two dimensions. In elastic systems, the impact parameter is uniformly distributed or, with other words, the molecular chaos assumption is valid independent of the density. In freely cooling systems, the molecular chaos assumption fails as soon as dissipation becomes strong enough so that convective shear modes are created.