206 citations · 5k across the 136 of their papers we have counts for
26 papers · 1 filter
Frustrated bearings
R. S. Pires, A. A. Moreira, H. J. Herrmann +1
In a bearing state, touching spheres (disks in two dimensions) roll on each other without slip. Here we frustrate a system of touching spheres by imposing two different bearing sta…
Simulating isothermal aging of snow
Roman Vetter, Stephan Sigg, Herman M. Singer +3
A Monte Carlo algorithm to simulate the isothermal recrystallization process of snow is presented. The snow metamorphism is approximated by two mass redistribution processes, surfa…
Collapse of orthotropic spherical shells
Gautam Munglani, Falk K. Wittel, Roman Vetter +2
We report on the buckling and subsequent collapse of orthotropic elastic spherical shells under volume and pressure control. Going far beyond what is known for isotropic shells, a…
Behavior of confined granular beds under cyclic thermal loading
Pavel S. Iliev, Elena Giacomazzi, Falk K. Wittel +3
We investigate the mechanical behavior of a confined granular packing of irregular polyhedral particles under repeated heating and cooling cycles by means of numerical simulations…
Kelvin-Helmholtz instability of the Dirac fluid of charge carriers on graphene
Rodrigo C. V. Coelho, Miller Mendoza, Mauro M. Doria +1
We provide numerical evidence that a Kelvin-Helmholtz instability occurs in the Dirac fluid of electrons in graphene and can be detected in current experiments. This instability ap…
Self-assembly and rheology of dipolar colloids in simple shear - studied by multi-particle collision dynamics
Dmitry Zablotsky, Elmars Blums, Hans J. Herrmann
Magnetic nanoparticles in a colloidal solution self-assemble in various aligned structures, which has a profound influence on the flow behavior. However, the precise role of the mi…
Invasion Percolation with a Hardening Interface under Gravity
C. L. N. Oliveira, Falk K. Wittel, J. S. Andrade +1
We propose a modified Invasion Percolation (IP) model to simulate the infiltration of glue into a porous medium under gravity in 2D. Initially, the medium is saturated with air and…
Coupled DEM-LBM method for the free-surface simulation of heterogeneous suspensions
A. Leonardi, F. K. Wittel, M. Mendoza +1
The complexity of the interactions between the constituent granular and liquid phases of a suspension requires an adequate treatment of the constituents themselves. A promising way…
Analysis of the velocity field of granular hopper flow
F. G. R. Magalhães, A. P. F. Atman, J. G. Moreira +1
We report the analysis of radial characteristics of the flow of granular material through a conical hopper. The discharge is simulated for various orifice sizes and hopper opening…
Packing of elastic wires in flexible shells
Roman Vetter, Falk K. Wittel, Hans J. Herrmann
The packing problem of long thin filaments that are injected into confined spaces is of fundamental interest for physicists and biologists alike. How linear threads pack and coil i…
Origins of barchan dune asymmetry: insights from numerical simulations
Eric J. R. Parteli, Orencio Durán, Mary C. Bourke +3
Barchan dunes --- crescent-shaped dunes that form in areas of unidirectional winds and low sand availability --- commonly display an asymmetric shape, with one limb extended downwi…
Finite-size scaling investigation of the liquid-liquid critical point in ST2 water and its stability with respect to crystallization
Tobias A. Kesselring, Erik Lascaris, Giancarlo Franzese +3
The liquid-liquid critical point scenario of water hypothesizes the existence of two metastable liquid phases---low-density liquid (LDL) and high-density liquid (HDL)---deep within…
Linear stability analysis of transverse dunes
Hygor P. M. Melo, Eric J. R. Parteli, José S. Andrade +1
Sand-moving winds blowing from a constant direction in an area of high sand availability form transverse dunes, which have a fixed profile in the direction orthogonal to the wind.…
Finite Element Simulation of Dense Wire Packings
Roman Vetter, Falk K. Wittel, Norbert Stoop +1
A finite element program is presented to simulate the process of packing and coiling elastic wires in two- and three-dimensional confining cavities. The wire is represented by thir…
Granular packings of cohesive elongated particles
R. C. Hidalgo, D. Kadau, T. Kanzaki +1
We report numerical results of effective attractive forces on the packing properties of two-dimensional elongated grains. In deposits of non-cohesive rods in 2D, the topology of th…
Why do Particle Clouds Generate Electric Charges?
Thomas Pähtz, Hans J. Herrmann, Troy Shinbrot
Grains in desert sandstorms spontaneously generate strong electrical charges; likewise volcanic dust plumes produce spectacular lightning displays. Charged particle clouds also cau…
New universality class for the fragmentation of plastic materials
G. Timar, J. Blomer, F. Kun +1
We present an experimental and theoretical study of the fragmentation of polymeric materials by impacting polypropylene particles of spherical shape against a hard wall. Experiment…
Simulation of Flow of Mixtures Through Anisotropic Porous Media using a Lattice Boltzmann Model
M. Mendoza, F. K. Wittel, H. J. Herrmann
We propose a description for transient penetration simulations of miscible and immiscible fluid mixtures into anisotropic porous media, using the lattice Boltzmann (LB) method. Our…
Hydrodynamic Theory for Reverse Brazil Nut Segregation and the Non-monotonic Ascension Dynamics
Meheboob Alam, Leonardo Trujillo, Hans J. Herrmann
Based on the Boltzmann-Enskog kinetic theory, we develop a hydrodynamic theory for the well known (reverse) Brazil nut segregation in a vibro-fluidized granular mixture. Using an a…
Anomalous distribution functions in sheared suspensions
Jens Harting, Hans J. Herrmann, Eli Ben-Naim
We investigate velocity probability distribution functions (PDF) of sheared hard-sphere suspensions. As observed in our Stokes flow simulations and explained by our single-particle…
Size distribution and structure of Barchan dune fields
Orencio Durán, Veit Schwämmle, Pedro G. Lind +1
Barchans are isolated mobile dunes often organized in large dune fields. Dune fields seem to present a characteristic dune size and spacing, which suggests a cooperative behavior b…
A driven two-dimensional granular gas with Coulomb friction
Olaf Herbst, Raffaele Cafiero, Annette Zippelius +2
We study a homogeneously driven granular gas of inelastic hard particles with rough surfaces subject to Coulomb friction. The stationary state as well as the full dynamic evolution…
Transport Phenomena and Structuring in Shear Flow of Suspensions near Solid Walls
A. Komnik, J. Harting, H. J. Herrmann
In this paper we apply the lattice-Boltzmann method and an extension to particle suspensions as introduced by Ladd et al. to study transport phenomena and structuring effects of pa…
Sedimentation of Oblate Ellipsoids at low and Moderate Reynolds numbers
F. Fonseca, H. J. Herrmann
In many applications to biophysics and environmental engineering, sedimentation of non-spherical particles for example: ellipsoids, is an important problem. In our work, we simulat…