Nonsmooth Mechanics and Analysis pp 233-245 | Cite as
Scaling Behaviour of Velocity Fluctuations in Slow Granular Flows
Abstract
Steric exclusions among particles lead to strong velocity fluctuations in a granular flow. Modelling the effective behaviour of granular materials depends on the extent and scaling properties of these fluctuations. We consider here slow granular flows of rigid particles simulated by a discrete element method. Bi-periodic boundary conditions allow for macroscopically homogeneous shearing up to large strains. We obtain thus reliable statistics for an accurate analysis of particle velocity fluctuations. We find that the probability distribution function of velocity components, evaluated from particle displacements, crucially depends on time resolution. It varies from stretched exponential to gaussian as the integration time is increased. On the other hand, the spatial power spectrum of the fluctuating velocity field is a power law, reflecting long range correlations and the self-affine nature of the fluctuations. Finally, by considering individual particle displacements, we show that the particles have a superdiffusive motion with respect to the mean background flow. These scaling behaviours bear a close analogy with the known scaling properties of turbulent fluid flows although the underlying physics is drastically different.
Keywords
granular media discrete element method plastic deformation steric exclusions probability density function space correlations superdiffusion turbulencePreview
Unable to display preview. Download preview PDF.
References
- Allen, M. P. and Tildesley, D. J. (1987). Computer Simulation of Liquids. Oxford University Press, Oxford.MATHGoogle Scholar
- de Gennes, P.-G. (1999). Granular matter: a tentative review. Reviews of Modern Physics, 71:S374–S382.CrossRefGoogle Scholar
- Feder, J. (1988). Fractals. Plenum press, NewYork.MATHGoogle Scholar
- Frisch, U. (1995). Turbulence, the Legacy of A. N. Kolmogorov. Cambridge University Press, Cambridge, England.MATHGoogle Scholar
- Hicher, P.-Y. (2000). Experimental behaviour of granular materials. In Cambou, B., editor, Behaviour of Granular Materials, pages 1–98, Wien. Springer.Google Scholar
- Jaeger, H. M., Nagel, S. R., and Behringer, R. P. (1996). Granular solids, liquids, and gases. Reviews of Modern Physics, 68(4):1259–1273.CrossRefGoogle Scholar
- Kuhn, M. (1999). Mechanics of Materials, 31:407.CrossRefGoogle Scholar
- Miller, B., O’Hern, C., and Behringer, R. P. (1996). Stress fluctuations for continously sheared granular materials. Phys. Rev. Lett., 77:3110–3113.CrossRefGoogle Scholar
- Misra, A. and Jiang, H. (1997). Measured kinematic fields in the biaxial shear of granular materials. Computers and Geotechnics, 20(3/4):267–285.CrossRefGoogle Scholar
- Moreau, J. J. (1988). Unilateral contact and dry friction in finite freedom dynamics, pages 1–82. Number 302.Google Scholar
- Moreau, J. J. (1993). New computation methods in granular dynamics. In Powders & Grains 93, page 227, Rotterdam. A. A. Balkema.Google Scholar
- Moreau, J. J. (1994a). Some numerical methods in multibody dynamics: Application to granular materials. European Journal of Mechanics A/Solids, supp.(4):93–114.MathSciNetGoogle Scholar
- Moreau, J. J. (1994b). Some numerical methods in multibody dynamics: application to granular materials. Eur. J. Mech. A, 13:93.MATHMathSciNetGoogle Scholar
- Moreau, J. J. (1997). Numerical investigation of shear zones in granular materials. In Wolf, D. E. and Grassberger, P., editors, Friction, Arching and Contact Dynamics, Singapore. World Scientific.Google Scholar
- Parrinello, M. and Rahman, A. (1980). Phys. Rev. Lett., 45:1196.CrossRefGoogle Scholar
- Radjai, F., Jean, M., Moreau, J. J., and Roux, S. (1996). Force distribution in dense two-dimensional granular systems. Phys. Rev. Lett., 77(2):274.CrossRefGoogle Scholar
- Radjai, F. and Roux, S. (2002). Turbulentlike fluctuations in quasistatic flow of granular media. Phys. Rev. Lett., 89:064302.CrossRefGoogle Scholar
- Rothenburg, L. and Bathurst, R. J. (1989). Analytical study of induced anisotropy in idealized granular materials. Geotechnique, 39:601–614.CrossRefGoogle Scholar
- Roux, S. and Radjai, F. (2001). Statistical approach to the mechanical behavior of granular media. In Aref, H. and Philips, J., editors, Mechanics for a New Millennium, pages 181–196, Netherlands. Kluwer Acad. Pub.Google Scholar
- Troadec, H., Radjai, F., Roux, S., and Charmet, J.-C. (2002). Model for granular texture with steric exclusions. Phys. Rev. E, 66:041305.CrossRefGoogle Scholar
- Wood, D. (1990). Soil behaviour and critical state soil mechanics. Cambridge University Press, Cambridge, England.MATHGoogle Scholar