Discrete Element Model Reference

The Discrete Element Model is the prerequisite for any work using the DEM solid particle models.


Theory	See Discrete Element Method in Theory.
Provided By	[physics continuum] > Models > Optional Models
Example Node Path	Continua > Physics 1 > Models > Discrete Element Model (DEM)
Requires	Optional Models: Lagrangian Multiphase
Properties	Key property is: Register Basic Contact Field Functions. See Discrete Element Model Properties.
Activates	Physics Models	Multi-Phase Interaction: Multiphase Interaction
	Field Functions	Contact Temperature The following field functions are activated when the Register Basic Contact Field Functions property is On: Contact Mass 0\|1 Contact Physical Radius 0\|1 Contact Poisson Ratio 0\|1 Contact Radius 0\|1 Contact Surface Velocity 0\|1 Contact Temperature 0\|1 Contact Youngs Modulus 0\|1
	Solvers	DEM Solver. See Discrete Element Method Solver.

If you set up Lagrangian phases with DEM particles, clearing the DEM model automatically deletes the Lagrangian phases, because they no longer serve any purpose in the simulation. To prevent the loss of those phases, clear the DEM Particles phase model in each Lagrangian phase before clearing the DEM continuum model.

Discrete Element Model Properties

Register Basic Contact Field Functions

When On and when the DEM Phase Interaction model is active, this activates the following field functions:

Contact Mass 0|1, Contact Physical Radius 0|1, Contact Poisson Ratio 0|1, Contact Radius 0|1, Contact Surface Velocity 0|1, Contact Temperature 0|1, Contact Youngs Modulus 0|1

The default is Off.

Discrete Element Method Solver

Grid Scale: Sets the scale of the grid cell to the particle diameter.
Reordering Frequency: Sets the number of iterations until Simcenter STAR-CCM+ reorders the sequence in which DEM particles are accessed in memory. The default value is 0 (no reordering).
Time Scale: Sets the allowed fraction of the Rayleigh wave limit (Eqn. (3244)).
Verbose: When On, provides more output for this value while the simulation is running. This property can be useful for debugging problems when they occur.
Smooth Large Particles: Smooths large particles on the Eulerian mesh for two-way coupling. This property is deprecated and will be removed in a future release.
Solver Frozen: When On, the solver does not update any quantity during an iteration. It is Off by default. This is a debugging option that can result in non-recoverable errors and wrong solutions due to missing storage. See Finite Volume Solvers Reference for details.
Void Fraction Limit: Sets the void fraction limit for particle smoothing.
Smoothing Radius: Sets the smoothing radius (normalized to the particle radius).
Smoothing Sigma: Sets the smoothing distribution sigma (normalized to the particle radius).
Static Timestep: Instructs Simcenter STAR-CCM+ to use the value of the time-step that you enter. This option should not be your first choice, as it can cause a failure to converge. The default setting of 0.0 leaves the dynamic calculation uninterrupted.
Skin: Sets a distance around each particle, the “skin”. Simcenter STAR-CCM+ runs contact detection only when the particle moves through a distance equal to the skin thickness. The default value is given as 0 for all particle types, but for non-convex polyhedral particles, the actual value is always at least 2% of particle diameter.