RT Journal Article T1 Ring kinetic theory for an idealized granular gas A1 Van Noije, T. P. C. A1 Ernst, M. H. A1 Brito López, Ricardo AB The dynamics of inelastic hard spheres is described in terms of the binary collision expansion, yielding the corresponding pseudo-liouville equation and BBGKY hierarchy for the reduced distribution functions. Based on cluster expansion techniques we derive the Boltzmann and ring kinetic equations for inelastic hard spheres. In the simple ring approximation, we calculate the structure factor S-perpendicular to(k,t) of vorticity fluctuations in a freely evolving, dilute granular gas. The kinetic theory result agrees with the result derived previously from fluctuating hydrodynamics. If the fluctuations in the flow field can be considered incompressible, S-perpendicular to(k,t) determines the spatial correlations in the flow velocities, which are of dynamic origin and exhibit long range r(-d)-behavior. The analytic results are compared with molecular dynamics simulations. PB Elsevier SN 0378-4371 YR 1998 FD 1998-03-01 LK https://hdl.handle.net/20.500.14352/58510 UL https://hdl.handle.net/20.500.14352/58510 LA eng NO © 1998 Elsevier Science B.V. Dedicated to J.M.J. van Leeuwen on the occasion of his 65th birthday. The authors want to thank J.A.G. Orza for performing molecular dynamics simulations, and H.J. Bussemaker and D. Montgomery for stimulating discussions. T.v.N. acknowledges support of the foundation `Fundamenteel Onderzoek der Materie (FOM)', which is financially supported by the Dutch National Science Foundation (NWO). R.B. acknowledges support from DGICYT (Spain) number PB94-0265. NO Fundamenteel Onderzoek der Materie (FOM) NO Dutch National Science Foundation (NWO) NO DGICYT (España) DS Docta Complutense RD 10 abr 2025