References of "Ludewig, François"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailCompaction of granular materials: experiments and contact dynamics simulations
Lumay, Geoffroy ULg; Ludewig, François ULg; Vandewalle, Nicolas ULg

in Journal of Physics: Conference Series (2006), 40

We present an original experimental study of the slow compaction dynamics for two- dimensional isotropic granular systems. Compaction dynamics is measured at three different scales : the macroscopic scale ... [more ▼]

We present an original experimental study of the slow compaction dynamics for two- dimensional isotropic granular systems. Compaction dynamics is measured at three different scales : the macroscopic scale through the normalized packing fraction ˜ ρ, the mesoscopic scale through the normalized fraction ˜ φ of domains ideally ordered in the system, and the microscopic scale through the grain mobility μ. The domains ideally ordered are found to obey a growth process dominated by the displacement of domain boundaries. We present also preliminary results of three-dimensional simulations with a model of contact dynamics. These results allow to discuss the difference between the two-dimensional and the three-dimensional cases. [less ▲]

Detailed reference viewed: 13 (1 ULg)
Full Text
Peer Reviewed
See detailReversing the Brazil nut effect
Ludewig, François ULg; Vandewalle, Nicolas ULg

in European Physical Journal E -- Soft Matter (2005), 18(4), 367-372

We propose a lattice model for studying the Brazil Nut Effect (BNE), i.e. the phase segregation occuring when a granular material is vertically shaked. The model considers the tap intensity and the ... [more ▼]

We propose a lattice model for studying the Brazil Nut Effect (BNE), i.e. the phase segregation occuring when a granular material is vertically shaked. The model considers the tap intensity and the mobility mu of the grains as the main physical parameters. Different mobilities for different grain species lead to segregation (BNE) patterns, reverse segregation (RBNE) patterns, "sandwhich" layered structures or vertical domains. A phase diagram (decompaction chi, mobility difference between both species Delta mu) is obtained in which the different phases are emphasized. In a narrow region of the diagram, different phases coexist. It is shown that the BNE segregation could be reversed by increasing the tap intensity or the characteristics of the grains. Numerical results are compared with earlier experimental works. [less ▲]

Detailed reference viewed: 28 (1 ULg)
Peer Reviewed
See detailA lattice model for BNE and RBNE
Ludewig, François ULg; Vandewalle, Nicolas ULg

in Powders and Grains 2005 (2005)

Detailed reference viewed: 14 (1 ULg)
Full Text
Peer Reviewed
See detailEffect of friction in a toy model of granular compaction
Ludewig, François ULg; Dorbolo, Stéphane ULg; Vandewalle, Nicolas ULg

in Physical Review E (2004), 70(5, Pt 1), 51304

A toy model of granular compaction which includes some resistance due to granular arches is proposed. In this model, the solid/solid friction of contacting grains is a key parameter and a slipping ... [more ▼]

A toy model of granular compaction which includes some resistance due to granular arches is proposed. In this model, the solid/solid friction of contacting grains is a key parameter and a slipping threshold omega(c) is defined. Realistic compaction behaviors have been obtained. Two regimes separated by a critical point omega(c)* of the slipping threshold have been emphasized: (i) a slow compaction with lots of paralyzed regions and (ii) an inverse logarithmic dynamics with a power-law scaling of grain mobility. Below the critical point omega(c)*, the physical properties of this frozen system become independent of omega(c). Above the critical point omega(c)*-i.e., for low friction values-the packing properties behave as described by the classical Janssen theory for silos. [less ▲]

Detailed reference viewed: 20 (7 ULg)
Peer Reviewed
See detailA Modified Tetris Model Including The Effect of Friction
Ludewig, François ULg; Dorbolo, Stéphane ULg; Caps, Hervé ULg et al

in Traffic and Granular Flow'03 (2003)

Detailed reference viewed: 7 (2 ULg)