Rotation of Box#

This example simulates a triangulation (box) rotation. It is recommended to visit DEM parameters for more detailed information on the concepts and physical meanings of the parameters in Lethe-DEM.

Features#

Solvers: lethe-particles
Rotating a triangulation

Files Used in This Example#

Parameter file: examples/dem/3d-grid-rotation-in-box/grid-rotation-box.prm

Description of the Case#

4000 particles are inserted in a rotating box and rotate with the box. In this example, the whole triangulation is rotated.

Parameter File#

Mesh#

The grid type in this example is a hyper_cube. Its dimensions are 0.04 m in every direction (from -0.02 m to 0.02 m), and it is refined 3 times.

subsection mesh
  set type               = dealii
  set grid type          = hyper_cube
  set grid arguments     = -0.02 : 0.02 : false
  set initial refinement = 3
end

Insertion Info#

An insertion box is defined inside the cubic domain. 4000 particles are inserted non-uniformly in the first iteration.

subsection insertion info
  set insertion method                               = volume
  set inserted number of particles at each time step = 4000
  set insertion frequency                            = 2000000
  set insertion box points coordinates               = -0.019, -0.019, -0.01 : 0.019, 0.019, 0.019
  set insertion distance threshold                   = 1.5
  set insertion maximum offset                       = 0.2
  set insertion prn seed                             = 19
end

Lagrangian Physical Properties#

The number of particles (4000) is equal to the specified inserted number of particles at each time step. This means that all the particles are inserted during the first insertion iteration (if the inserted number of particles fits inside the specified insertion box).

subsection lagrangian physical properties
  set g                        = 0.0, 0.0, -9.81
  set number of particle types = 1
  subsection particle type 0
    set size distribution type            = uniform
    set diameter                          = 0.001
    set number of particles               = 4000
    set density particles                 = 1000
    set young modulus particles           = 1000000
    set poisson ratio particles           = 0.3
    set restitution coefficient particles = 0.3
    set friction coefficient particles    = 0.1
    set rolling friction particles        = 0.05
  end
  set young modulus wall           = 1000000
  set poisson ratio wall           = 0.3
  set restitution coefficient wall = 0.3
  set friction coefficient wall    = 0.1
  set rolling friction wall        = 0.05
end

Model Parameters#

subsection model parameters
  subsection contact detection
    set contact detection method                = dynamic
    set dynamic contact search size coefficient = 0.9
    set neighborhood threshold                  = 1.3
  end
  set particle particle contact force method    = hertz_mindlin_limit_overlap
  set particle wall contact force method        = nonlinear
  set rolling resistance torque method          = constant_resistance
  set integration method                        = velocity_verlet
end

Simulation Control#

subsection simulation control
  set time step        = 1e-5
  set time end         = 5
  set log frequency    = 1000
  set output frequency = 1000
end

Running the Simulation#

This simulation can be launched by:

lethe-particles grid-rotation-box.prm

Results#

Animation of the rotating box simulation: