SOFT-Granular Media & powders

SOFT-Complex Fluids & Solids

Granular Media and Powders

This theme deals with the static and flow behaviors of granular media and cohesive powders, especially in the dense regime. A large effort has been devoted in the group over the last two decades to develop an hydrodynamic description of dense granular flows for idealized systems. We now extend this approach to more complex situations, such as the question of the forces exerted on solid objects immersed in grains, silo flows, flow of cohesive granular materials, powders compaction and the mechanics of entangled media like fibre bundles.


Rheology of Dense Granular Flows

Participants: Y. Forterre, B. Metzger, O. Pouliquen
Collaboration: B. Andreotti (PMMH), I. Einav (Sydney University), N. Vandenberghe (IRPHE), F. Guillard (Sydney University), society SAFE METAL, F. Bertails-Descoubes (INRIA Grenoble)
PhD/post-doc: P. Jop (PhD 2003-2006), A. Reddy (post-doc 2009-2010), F. Guillard (AMN 2010-2013), P. Rognon (post-doc, 2011-2012)

Most granular flows encountered in industry and geophysics occur in an intermediate regime between the ‘solid’ regime described in soil mechanics and the ‘gas’ regime described by the kinetic theory. In this ‘dense’ or ‘liquid’ regime, the concentration is large and both collision and enduring contacts are important making difficult the derivation of constitutive equations. Over the last two decades, we have contributed to the development of a continuous description of dense granular flows in terms of a visco-plastic frictional rheology. This approach provides a frist order description of many flow configurations but has also limitation, in particular for slow flows where nonlocal effects appear. We investigate these phenomena in simple geometries, such as flows down inclined planes, simple shear flow or Couette flow.  

Granular Fluid/Structure Interaction

Participants: P. Aussillous, Y. Forterre, O. Pouliquen
Collaboration: N. Vandenberghe (IRPHE), F. Guillard (Sydney University), society SAFE METAL, F. Bertails-Descoubes (INRIA Grenoble)
PhD/post-doc: F. Guillard (AMN 2010-2013), J John Soundar Jerome (2013-2014, ANR CRASH/Labex), V. Paume (CIFRE 2020-),

Understanding the interaction between a granular flow and a solid object has applications ranging from industry (extraction and agriculture machines, locomotion of vehicules and inspection robots, balistics) to geophysics (impact cratering) to biology (animal locomotion in particulate soil, root anchoring and growth). We address this question using experiments, continuum modeling and discrete numerical simulations, in the light of the progress made on the rheology of granular flows.  Investigation includes the drag and lift forces exerted on an object moving in a static granular materials, the force on large particles immersed in a granular flow in relation with particle size-segregation, the impact of a solid object on a dry or wet granular bed, the penetration of complex objects into a granular soil in relation with mining equipments.

Silo Flows

Participants: Pascale Aussillous, Blanche Dalloz
Collaborations: Université de Béchar (Algérie) – Institut de radioprotection et de Sûreté Nucléaire (IRSN), J-Y Lagrée and L. Staron (IJLRA), H. Capart (Taïwan)
PhD/Post-doc: Yixian Zhou (IRSN, 2013-2016), M. Benyamine (thèse de doctorat d’état), Z. Zou (IRSN, 2016-2019)

This subject was initiated in 2012 as part of a state thesis at the University of Béchar in Algeria. We experimentally studied the emptying of a silo containing a bidisperse mixture of grains, for two types of silos (rectangular and cylindrical, flat-bottomed).  A simple physical model based on a mixing law was proposed and validated by discrete simulations. In collaboration with IRSN, we are now studying the dynamics of silo discharge when the grains are ejected by a pressurized gas using a combination of experiments and two-phase contiuum modeling in collaboration with the Institut d’Alembert and the experimental shock team of IUSTI.

Cohesive Powders

Participants: B. Dalloz, M. Nicolas, O. Pouliquen
Collaboration: P. Sornay, CEA, PY Lagrée (IJLRA), A. Sauret (CNRS/Santa-Barbara), Saint-Gobain/CREE Cavaillon
PhD/post-doc: A. Benedetti, J.-E. Mathonnet (PhD, CEA), A. Gens (PhD Ministère 2018-), S. Mandal (post-doc ANR, 2018-)

Characterization and prediction of the ‘flowability’ of powders are of paramount importance in many industries. However, our understanding of the flow of powders like cement or flour is sparse compared to the flow of (dry) granular media like sand. The main difficulty arises because of the presence of adhesive forces between the grains, preventing smooth and continuous flows. Several tests are used in industrial contexts to probe and quantify the ‘flowability’ of powders. However, they remain empirical and would benefit from a detailed study of the physics controlling the flow dynamics. We address the flow and compaction of powders using experiments on model cohesive granular materials and discrete numerical simulations. Several configuration are investigated, such as powder flows under vertical or horizontal vibrations, flow in silo, flow down inclined planes or granular collapse of cohesive medium. 


  • S. Mandal, M. Nicolas, O. Pouliquen. Rheology of Cohesive Granular Media: Shear Banding, Hysteresis, and Nonlocal Effects. Phys. Rev. X 11 21017 (2021) 10.1103/PhysRevX.11.021017
  • S. Laidaoui, P. Aussillous, M. Djermane, B. Dalloz-Dubrujeaud, B Discharge flow of granular media from rectangular silos: role of an obstacle and modelling by an orifice at the corner. Mechanics & Industry. 21 516 (2020) 10.1051/meca/2020048 
  • A. Gans, O. Pouliquen, M. Nicolas. Cohesion-controlled granular material. Phys. Rev. E. 101 32904 (2020) 10.1103/PhysRevE.101.032904 
  • Z. Zou, P. Ruyer, PY. Lagree, P. Aussillous. Discharge of a silo through a lateral orifice: Role of the bottom inclination versus friction. Phys. Rev. E. 102 52902 (2020) 10.1103/PhysRevE.102.052902 
  • S. Mandal, M. Nicolas, O. Pouliquen, Insights into the rheology of cohesive granular media. PNAS 117 8366-8373 (2020) 10.1073/pnas.1921778117 
  • M Ben Amar, L. Limat, O. Pouliquen, E. Villermaux. Tribute to an exemplary man : Yves Couder. Comptes Rendus Mécanique. 348 393-395 (2020) 10.5802/crmeca.35
  • Y. Zhou, P.-Y. Lagrée, S. Popinet, P. Ruyer, and P. Aussillous. Gas-assisted discharge flow of granular media from silos. Phys. Rev. Fluids 4, 124305 (2019)
  • Y. Forterre, O. Pouliquen. Physics of particulate flows: From sand avalanche to active suspensions in plants. C. R. Physique 19, 271-284 (2018) pdf
  • C.-Y. Hung, P. Aussillous, H. Capart. Granular surface avalanching induced by drainage from a narrow silo. J. Fluid Mech. 856, 444-469 (2018) pdf
  • Y. Zhou, P.-Y. Lagrée, S. Popinet, P. Ruyer, P. Aussillous. Experiments on, and discrete and continuum simulations of, the discharge of granular media from silos with a lateral orifice. J. Fluid Mech. 829, 459-485 (2017) pdf
  • J-E. Mathonnet, P. Sornay, M. Nicolas, B. Dalloz-Dubrujeaud. Compaction of non-cohesive and cohesive granular materials under vibrations: experiments and stochastic model. Phys. Rev. E 95 042904 (2017)
  • M. Nicolas. A comprehensive study on the behavior of a rigid block on an oscillating ground with friction, elastic and viscous forces. Int. J. Nonlinear Mech.93, 21-29 (2017)
  • F. Guillard, Y. Forterre, O. Pouliquen. Scaling laws for segregation force in sheared dense granular flows. J. Fluid Mech. 807, R1 (2016) pdf
  • J. J. S. Jerome, N. Vandenberghe, Y. Forterre. Unifying impacts in granular matter from quicksand to cornstarch. Phys. Rev. Lett. 117, 098003 (2016) pdf
  • Y. Zhou, P. Ruyer, P. Aussillous, Discharge flow of a bidisperse granular media from a silo: discrete particle simulations, Phys. Rev. E. 92, 062204 (2015) pdf
  • M. Benyamine, M. Djermane, B. Dalloz-Dubrujeaud, P. Aussillous. Discharge flow of a bidisperse granular media from a silo, Phys. Rev. E. 90, 032201 (2014) pdf
  • F. Guillard, Y. Forterre, O. Pouliquen. Lift forces in granular media. Phys Fluids 26, 043301 (2014) pdf
  • P. G. Rognon, T. Miller, B. Metzger, I. Einav. Long-range wall perturbations in dense granular flows. J. Fluid Mech. vol. 764, pp. 171-192 (2014) (2014_rognon_jfm)
  • T. K. Nguyen, N. Benhamed, P.-Y. Hicher, M. Nicolas. An experimental investigation into the effects of low plastic fines content on the behaviour of sand/silt mixtures. European Journal of Environmental and Civil Engineering (2014)
  • B. Andreotti, Y. Forterre, O. Pouliquen. Granular media: between fluid and solid. [book] Cambridge University Press (2013)
  • F. Guillard, Y. Forterre, O. Pouliquen. Depth-independent drag force induced by stirring in granular media. Phys. Rev. Lett. 110, 138303 (2013) pdf
  • T. Miller P. Rognon, B. Metzger, I. Einav. Eddy Viscosity in Dense Granular Flows. Phys. Rev. Lett. 111, 058002 (2013) (2013_rognon_prl)
  • D. Griffani, P. Rognon, B. Metzger, I. Einav. How vortices enhance transfers? (2013) Phys. Fluids 25, 093301 (2013) (2013_rognon_pof)
  • A. Benedetti, P. Sornay, B. Dalloz & M. Nicolas. An angular particle sliding down a transversally vibrated smooth plane. Phys. Rev. E, 85, 011307 (2012)
  • B. Andreotti, Y. Forterre, O. Pouliquen. Les milieux granulaires – entre fluide et solide. EDP Sciences [book] (2011) Editor link
  • A. Reddy, Y. Forterre, O. Pouliquen. Evidence of mechanically activated processes in slow granular flows. Phys. Rev. Lett 106, 108301 (2011) pdf
  • O. Pouliquen, Y. Forterre. A non-local rheology for dense granular flows. Phil. Trans. R. Soc. A 367, 5091 (2009) pdf
  • Y. Forterre, O. Pouliquen. Flows of dense granular media. Ann. Rev. Fluid. Mech. 40, 1 (2008) pdf
  • P. Jop, Y. Forterre, O. Pouliquen. Initiation of granular surface flows in a narrow channel. Physics of Fluids 19, 088102 (2007) pdf
  • O. Pouliquen, C. Cassar, P. Jop, Y. Forterre, M. Nicolas. Flows of dense granular material: towards simple constitutive laws. J. Stat. Mech. P07020 (2006) pdf
  • Y. Forterre. Kapitza waves gives support for three-dimensional granular flow rheology. J. Fluid. Mech. 563, 123 (2006) pdf
  • P. Jop, Y. Forterre, O. Pouliquen. A constitutive law for dense granular flows. Nature 441, 727 (2006) pdf
  • P. Jop, Y. Forterre, O. Pouliquen. Crucial role of side walls for granular surface flows: consequence for the rheology. J. Fluid Mech. 541, 167 (2005) pdf
  • O. Pouliquen. Velocity Correlations in Dense Granular Flows. Phys. Rev. Lett. 93, 248001 (2004)
  • Y. Forterre , O. Pouliquen. Long-surface-wave instability in dense granular flows. J. Fluid Mech. 486, 21 (2003) pdf
  • O. Pouliquen, M. Belzons, M. Nicolas. Fluctuating particle motion during shear induced granular compaction. Phys. Rev. Lett. 91 (1) 014301 (2003)
  • Y. Forterre , O. Pouliquen. Stability analysis of rapid granular chute flows: formation of longitudinal vortices. J. Fluid Mech. 467, 361 (2002) pdf
  • O. Pouliquen, Y. Forterre. Friction law for dense granular flows: application to the motion of a mass down a rough inclined plane. J. Fluid Mech. 453, 133 (2002) pdf
  • O. Pouliquen, Y. Forterre, S. Le Dizes. Slow dense granular flows as a self-induced process. Advances in complex Systems 4, 441 (2001) pdf
  • Y. Forterre , O. Pouliquen. Longitudinal vortices in granular flows. Phys. Rev. Lett. 86, 5886 (2001) pdf
  • M. Nicolas, P. Duru & O. Pouliquen. Compaction of a granular material under cyclic shear. Eur. Phys. J. E 3, 309–314 (2000)