Granular DEM

This is work by Christoph Kloss and Christoph Goniva at the Johannes Kepler University (JKU) in Austria, on discrete element modeling (DEM) using their LIGGGHTS software package which extends the granular package in LAMMPS. All but the last of these movies are for particle-only systems. The final movie shows a new capability he and a colleague have developed to perform hybrid simulations of DEM particles in a background fluid, which has been done in LIGGHTS by coupling LAMMPS to the OpenFoam computational fluid dynamics (CFD) package. The visualizations were performed with Paraview.

(a) Speed-up of particle loading simulations by removing particles at rest from the simulation.

(b) Particles flowing into and out of a hopper.

(c) A shear force is exerted on the particles via moving walls.

(d) Modified version of the LAMMPS examples/pour/in.pour simulation, done in si units, with more sophisticated visualization.

(e) Illustrates how granular particles can be lumped together as a rigid body. This technique could be used to implement the so-called “multi-sphere method” where non-spherical particles are modelled by multiple spheres.

(f) Mimics the shrinking of particles in an industrial process, e. g. in a blast furnace or other processes involving combustion. If the particles are in a predefined region, their diameter is reduced over time.

(g) Particles falling into a basin filled with fluid (assumption: the fluid is at rest, no 2-way coupling) and experiencing a drag force. For more realistic results, see the last movie of a coupled DEM-CFD simulation.

(h) Simulation of a partially fluidized bed where a force is added in a region, which fluidizes the particles. For more realistic results, see the last movie of a coupled DEM-CFD simulation.

(i) A fully-coupled parallel DEM-CFD simulation using LAMMPS and OpenFoam.