Discrete Element Method (DEM)

The discrete element method (DEM) solver in Lethe is called lethe-particles and supports two-dimensional and three-dimensional simulations. In simulation_control, the general simulation parameters (for example, time-step, end time) are defined. The timer and test sections are used for timing the classes and functions, and testing the reproducibility of the results. In model parameters, we define the simulation models, including particle-particle and particle-wall contact models. In the lagrangian physical properties section, particles and walls physical properties are defined. The mesh section defines the simulation triangulation and refinements. The insertion info section defines every parameters related to each insertion method available in Lethe, i.e. the insertion box and insertion frequency for the volume insertion method. In the floating walls section, hyperplanes defined as mathematical planes can be added to the simulation domain to create walls in the simulation domain. In the solid objects section, surface meshes can be defined and their motion can be controlled during a simulation. In the boundary conditions section, simulation domain boundaries can be defined as walls, outlets or they can get periodicity, rotation or translation. The post-processing` can activate the post-processing lagrangian and force chains visualization tools. The particle ray tracing section defines the parameters used by the lethe-particles-ray-tracing application to simulate the propagation of photons (or rays) through the simulation domain to reconstruct the surface made by particle using the same principles as profilometry. This applications uses a lot of the same section as for the DEM solver, such as mesh, and insertion_info which is why it is included here.

• Simulation Control
• Test
• Timer
• Model Parameters
• Lagrangian Physical Properties
• Mesh
• Insertion Info
• Floating Wall
• Solid Objects
• Boundary Conditions
• Post-processing
• Particle Ray Tracing