Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-27T08:54:50.041Z Has data issue: false hasContentIssue false

Role of Molecular Chaos in Granular FluctuatingHydrodynamics

Published online by Cambridge University Press:  18 July 2011

Get access

Abstract

We perform a numerical study of the fluctuations of the rescaled hydrodynamic transversevelocity field during the cooling state of a homogeneous granular gas. We are interestedin the role of Molecular Chaos for the amplitude of the hydrodynamic noise and itsrelaxation in time. For this purpose we compare the results of Molecular Dynamics (MD,deterministic dynamics) with those from Direct Simulation Monte Carlo (DSMC, randomprocess), where Molecular Chaos can be directly controlled. It is seen that the large timedecay of the fluctuation’s autocorrelation is always dictated by the viscosity coefficientpredicted by granular hydrodynamics, independently of the numerical scheme (MD or DSMC).On the other side, the noise amplitude in Molecular Dynamics, which is known toviolate the equilibrium Fluctuation-Dissipation relation, is not alwaysaccurately reproduced in a DSMC scheme. The agreement between the two models improves ifthe probability of recollision (controlling Molecular Chaos) is reduced by increasing thenumber of virtual particles per cells in the DSMC. This result suggests that DSMC is notnecessarily more efficient than MD, if the real number of particles is small(~103 ± 104) and if one is interested in accurately reproducefluctuations. An open question remains about the small-times behavior of theautocorrelation function in the DSMC, which in MD and in kinetic theory predictions is nota straight exponential.

Type
Research Article
Copyright
© EDP Sciences, 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Barrat, A., Loreto, V., Puglisi, A.. Temperature probes in binary granular gases. Physica A, 334 (2004), No. 3-4, 513523. CrossRefGoogle Scholar
G. A. Bird. Molecular Gas Dynamics and the Direct Simulation of Gas Flows. Clarendon, Oxford, 1994.
Brey, J. J., Garcia de Soria, M. I., Maynar, P.. Breakdown of the fluctuation-dissipation relations in granular gases. Europhys. Lett., 84 (2008), No. 2, 24002. CrossRefGoogle Scholar
Brey, J. J., Dufty, J. W., Kim, C. S., Santos, A.. Hydrodynamics for granular flow at low density. Phys. Rev. E, 58 (1998), No. 4, 46384653. CrossRefGoogle Scholar
Brey, J. J., Maynar, P., Garcia de Soria, M. I.. Fluctuating hydrodynamics for dilute granular gases. Phys. Rev. E, 79 (2009), No. 5, 051305. CrossRefGoogle ScholarPubMed
Brey, J. J., Ruiz-Montero, M. J.. Validity of the boltzmann equation to describe low-density granular systems. Phys. Rev. E, 69 (2004), No. 1, 011305. CrossRefGoogle ScholarPubMed
Brey, J. J., Ruiz-Montero, M. J., Moreno, F.. Instability and spatial correlations in a dilute granular gas. Phys. Fluids, 10 (1008), No. 11, 29762982. CrossRefGoogle Scholar
Brey, J. J., Ruiz-Montero, M. J., Moreno, F.. Steady-state representation of the homogeneous cooling state of a granular gas. Phys. Rev. E, 69 (2004), No. 051303–. CrossRefGoogle ScholarPubMed
Brey, J.J., de Soria, M.I.G., Maynar, P., Ruiz-Montero, M.J.. Energy fluctuations in the homogeneous cooling state of granular gases. Phys. Rev. E, 70 (2004), No. 1, 011302. CrossRefGoogle ScholarPubMed
Brey, J.J., Ruiz-Montero, M.J.. Average energy and fluctuations of a granular gas at the threshold of the clustering instability. Granular Matter, 10 (2007), No. 1, 5359. CrossRefGoogle Scholar
Costantini, G., Puglisi, A.. Fluctuating hydrodynamics for dilute granular gases: a Monte Carlo study. Phys. Rev. E, 82 (2010), No. 1, 011305. CrossRefGoogle ScholarPubMed
Costantini, G., Puglisi, A., Marini Bettolo Marconi, U.. Granular Brownian ratchet model. Phys. Rev. E, 75 (2007), No. 6, 061124–. CrossRefGoogle ScholarPubMed
Costantini, G., Puglisi, A., Marini Bettolo Marconi, U.. Velocity fluctuations in a one dimensional inelastic Maxwell model. J. Stat. Mech., (2008), P08031. Google Scholar
Dufty, J. W., Brey, J. J.. Green-Kubo expressions for a granular gas. J. Stat. Phys., 109 (2002), No. 3-4, 433448. CrossRefGoogle Scholar
Eggers, J.. Sand as Maxwell’s demon. Phys. Rev. Lett., 83 (1999), No. 25, 53225325. CrossRefGoogle Scholar
Feitosa, K., Menon, N.. Breakdown of energy equipartition in a 2d binary vibrated granular gas. Phys. Rev. Lett., 88 (2002), No. 19, 198301. CrossRefGoogle Scholar
Garcia, A. L., Malek Mansour, M., Lie, G. C., Mareschal, M., Clementi, E.. Hydrodynamic fluctuations in a dilute gas under shear. Phys. Rev. A, 36 (1987), No. 9, 43484355. CrossRefGoogle Scholar
Goldhirsch, I.. Scales and kinetics of granular flows. Chaos, 9 (1999), No. 3, 659672. CrossRefGoogle ScholarPubMed
Goldhirsch, I., Zanetti, G.. Clustering instability in dissipative gases. Phys. Rev. Lett., 70 (1993), No. 11, 16191622. CrossRefGoogle ScholarPubMed
R. Kubo, M. Toda, N. Hashitsume. Statistical physics II: Nonequilibrium stastical mechanics. Springer, Berlin, 1991.
L. D. Landau, E. M. Lifchitz. Physique Statistique. Éditions MIR, Moscow, 1967.
Lutsko, J. F.. Molecular chaos, pair correlations, and shear-induced ordering of hard spheres. Phys. Rev. Lett., 77 (1996), No. 11, 22252228. CrossRefGoogle ScholarPubMed
Lutsko, J. F.. A model for the atomic-scale structure of the homogeneous cooling state of granular fluids. Phys. Rev. E, 63 (2001), No. 6, 061211. CrossRefGoogle ScholarPubMed
Mansour Malek, M., Garcia, A. L., Lie, G. C., Clementi, E.. Fluctuating hydrodynamics in a dilute gas. Phys. Rev. Lett., 58 (1987), No. 9, 874877. CrossRefGoogle Scholar
Marini Bettolo Marconi, U., Puglisi, A.. Mean-field model of free-cooling inelastic mixtures. Phys. Rev. E, 65 (2002), No. 5, 051305. Google ScholarPubMed
Marini Bettolo Marconi, U., Puglisi, A., Rondoni, L., Vulpiani, A.. Fluctuation-dissipation: Response theory in statistical physics. Phys. Rep., 461 (2008), No. 4-6, 111195. CrossRefGoogle Scholar
Maynar, P., de Soria, M. I. G., Trizac, E.. Fluctuating hydrodynamics for driven granular gases. Eur. Phys. J. Special Topics, 170 (2009), No. 1, 123139. CrossRefGoogle Scholar
Pagnani, R., Marini Bettolo Marconi, U., Puglisi, A.. Driven low density granular mixtures. Phys. Rev. E, 66 (2002), No. 5, 051304. CrossRefGoogle ScholarPubMed
T. Pöschel, N. Brilliantov, editors. Granular Gas Dynamics. Lecture Notes in Physics 624. Springer, Berlin, 2003.
T. Pöschel, S. Luding, editors.Granular Gases. Lecture Notes in Physics 564. Springer, Berlin, 2001.
Puglisi, A., Baldassarri, A., Loreto, V.. Fluctuation-dissipation relations in driven granular gases. Physical Review E, 66 (2002), No. 6, 061305. CrossRefGoogle ScholarPubMed
Puglisi, A., Baldassarri, A., Vulpiani, A.. Violations of the Einstein relation in granular fluids: the role of correlations. J. Stat. Mech., (2007), P08016. CrossRefGoogle Scholar
A. Sarracino, D. Villamaina, G. Costantini, A. Puglisi. Granular brownian motion. J. Stat. Mech., (2010) P04013.
Sarracino, A., Villamaina, D., Gradenigo, G., Puglisi, A.. Irreversible dynamics of a massive intruder in dense granular fluids. Europhys. Lett., 92 (2010), No. 3, 34001. CrossRefGoogle Scholar
van Noije, T. C. P., Ernst, M. H., Brito, R., Orza, J. A. G.. Mesoscopic theory of granular fluids. Phys. Rev. Lett., 79 (1007), No. 3, 411414. CrossRefGoogle Scholar
D. Villamaina, A. Puglisi, A. Vulpiani. The fluctuation-dissipation relation in sub-diffusive systems: the case of granular single-file diffusion. J. Stat. Mech., (2008), L10001.
Visco, P., Puglisi, A., Barrat, A., van Wijland, F., Trizac, E.. Energy fluctuations in vibrated and driven granular gases. Eur. Phys. J. B, 51 (2006), No. 3, 377387.CrossRefGoogle Scholar