Van Noije, T. P. C.Ernst, M. H.Brito López, Ricardo2023-06-202023-06-201998-051063-651X10.1103/PhysRevE.57.R4891https://hdl.handle.net/20.500.14352/58509© 1998 The American Physical Society. The authors want to thank J. A. G. Orza for his help in performing the simulations. T.v.N. acknowledges support of the foundation ‘‘Fundamenteel Onderzoek der Materie (FOM),’’ which is financially supported by the Dutch National Science Foundation (NOW). R.B. acknowledges support from DGICYT (Spain) Grant No. PB94-0265.The clustering instability in freely evolving granular fluids manifests itself in the density-density correlation function and structure factor. These functions are calculated from fluctuating hydrodynamics. As time increases, the structure factor of density fluctuations develops a maximum, which shifts to smaller wave numbers (growing correlation length). Furthermore, the inclusion of longitudinal velocity fluctuations changes long-range correlations in the flow field qualitatively and extends the validity of the theory for spatial velocity correlations to higher inelasticities. The theoretical predictions agree well with two-dimensional molecular-dynamics simulations.engjournal articlehttp://pre.aps.org/pdf/PRE/v57/i5/pR4891_1http://pre.aps.orghttp://arxiv.org/pdf/cond-mat/9710102v1open access536GasesTermodinámica2213 Termodinámica