The shear behavior of granular materials immersed in a viscous fluid depends on fluid properties (viscosity, density), particle properties (size, density) and boundary conditions (shear rate, confining pressure). Using computational fluid dynamics simulations coupled with molecular dynamics for granular flow, and exploring a broad range of the values of parameters, we show that the parameter space can be reduced to a single parameter that controls the packing fraction and effective friction coefficient. This control parameter is a modified inertial number that incorporates viscous effects.

VL - 140 UR - http://www.epj-conferences.org/10.1051/epjconf/201714009044 JO - EPJ Web Conf. ER - TY - JOUR T1 - Viscoinertial regime of immersed granular flows JF - Physical Review E Y1 - 2017 A1 - L. Amarsid A1 - Jean-Yves Delenne A1 - Patrick Mutabaruka A1 - Yann Monerie A1 - Perales, F. A1 - Farhang Radjaï AB -By means of extensive coupled molecular dynamics–lattice Boltzmann simulations, accounting for grain dynamics and subparticle resolution of the fluid phase, we analyze steady inertial granular flows sheared by a viscous fluid. We show that, for a broad range of system parameters (shear rate, confining stress, fluid viscosity, and relative fluid-grain density), the frictional strength and packing fraction can be described by a modified inertial number incorporating the fluid effect. In a dual viscous description, the effective viscosity diverges as the inverse square of the difference between the packing fraction and its jamming value, as observed in experiments. We also find that the fabric and force anisotropies extracted from the contact network are well described by the modified inertial number, thus providing clear evidence for the role of these key structural parameters in dense suspensions.

VL - 96 IS - 1 JO - Phys. Rev. E ER - TY - Generic T1 - AIP Conference ProceedingsTumbling sandpiles in a fluid T2 - 7th International Conference on Micromechanics of Granular Media (Powders and Grains) Y1 - 2013 A1 - Farhang Radjaï A1 - Vincent Topin A1 - Perales, F. A1 - Yann Monerie ED - Yu, A ED - Dong, K ED - Yang, R AB -By means of contact dynamics simulations interfaced with computational fluid dynamics, we analyze the effect of a suspending fluid on the dynamics of collapse and spread of a granular column. We find that the runout distance increases as a power law with the aspect ratio of the column and, for a given aspect ratio, it may be the same in the grain-inertial and fluid-inertial regimes but with considerably longer duration in the latter case. We show that, in both viscous and fluid-inertial regimes, this behavior results from compensation between two effects of the fluid: 1) reduction of the kinetic energy during collapse and 2) enhancement of the flow by lubrication during spread.

JF - 7th International Conference on Micromechanics of Granular Media (Powders and Grains) PB - AIP CY - JUL 08-12 2013 Sydney, AUSTRALIA VL - Book Series: AIP Conference Proceedings POWDERS AND GRAINS 2013 ER - TY - Generic T1 - GRANULAR SLUMPING IN A FLUID : FOCUS ON RUNOUT DISTANCES T2 - 3rd International Conference on Particle-based Methods Y1 - 2013 A1 - Vincent Topin A1 - Yann Monerie A1 - Perales, F. ED - Bischoff, M ED - Ramm, E ED - Onate, E JF - 3rd International Conference on Particle-based Methods CY - SEP 18-20 2013 Stuttgart, GERMANY VL - PARTICLE-BASED METHODS III: FUNDAMENTALS AND APPLICATIONS ER - TY - JOUR T1 - Collapse Dynamics and Runout of Dense Granular Materials in a Fluid JF - Physical Review Letters Y1 - 2012 A1 - Vincent Topin A1 - Yann Monerie A1 - Perales, F. A1 - Farhang Radjaï VL - 109 IS - 18 JO - Phys. Rev. Lett. ER - TY - JOUR T1 - Tensile strength and fracture of cemented granular aggregates JF - The European Physical Journal E Y1 - 2012 A1 - Rafik Affès A1 - Jean-Yves Delenne A1 - Yann Monerie A1 - Farhang Radjaï A1 - Vincent Topin AB -Cemented granular aggregates include a broad class of geomaterials such as sedimentary rocks and some biomaterials such as the wheat endosperm. We present a 3D lattice element method for the simulation of such materials, modeled as a jammed assembly of particles bound together by a matrix partially filling the interstitial space. From extensive simulation data, we analyze the mechanical properties of aggregates subjected to tensile loading as a function of matrix volume fraction and particle-matrix adhesion. We observe a linear elastic behavior followed by a brutal failure along a fracture surface. The effective stiffness before failure increases almost linearly with the matrix volume fraction. We show that the tensile strength of the aggregates increases with both the increasing tensile strength at the particle-matrix interface and decreasing stress concentration as a function of matrix volume fraction. The proportion of broken bonds in the particle phase reveals a range of values of the particle-matrix adhesion and matrix volume fraction for which the cracks bypass the particles and hence no particle damage occurs. This limit is shown to depend on the relative toughness of the particle-matrix interface with respect to the particles.

VL - 35 IS - 11 JO - Eur. Phys. J. E ER - TY - Generic T1 - Modeling Porous Granular Aggregates T2 - 9th International Workshop on Buifurcation and Degradation in Geomaterials (IWBDG 2011) Y1 - 2011 A1 - Rafik Affès A1 - Vincent Topin A1 - Jean-Yves Delenne A1 - Yann Monerie ED - Stéphane Bonelli ED - Dascalu, Cristian ED - François Nicot AB -We rely on 3D simulations based on the Lattice Element Method (LEM) to analyze the failure of porous granular aggregates under tensile loading. We investigate crack growth by considering the number of broken bonds in the particle phase as a function of the matrix volume fraction and particle-matrix adhesion. Three regimes are evidenced, corresponding to no particle damage, particle abrasion and particle fragmentation, respectively. We also show that the probability density of strong stresses falls off exponentially at high particle volume fractions where a percolating network of jammed particles occurs. Decreasing the matrix volume fraction leads to increasingly broader stress distribution and hence a higher stress concentration. Our findings are in agreement with 2D results previously reported in the literature.

JF - 9th International Workshop on Buifurcation and Degradation in Geomaterials (IWBDG 2011) PB - Springer Netherlands CY - MAY 23-26 2011 Porquerolles, FRANCE VL - Springer Series in Geomechanics and Geoengineering - ADVANCES IN BIFURCATION AND DEGRADATION IN GEOMATERIALS SN - 978-94-007-1420-5 ER -