DEM Boundary Forces Model Reference


Model Name	DEM Boundary Forces
Theory	Particle Equations of Motion
Provided By	[physics continuum] > Models > Optional Models
Example Node Path	Continua > Physics 1 > Models > DEM Boundary Forces
Requires	Optional Models: Lagrangian Multiphase Optional Models: Discrete Element Method (DEM)
Activates	Boundary Inputs	`DEM Boundary Force Accumulation`. See DEM Boundary Forces Boundary Settings.
	Reports	DEM Force, DEM Moment. See DEM Boundary Forces Reports.
	Field Functions	Average DEM Total Force, DEM Total Impulse, Maximum Magnitude DEM Total Force. See DEM Boundary Forces Field Functions.

This model is activated automatically when you select DEM Force and Moment as external force in a Dynamic Fluid Body Interaction (DFBI) simulation. See DEM Force and Moment.

DEM Boundary Forces Boundary Settings

Wall

DEM Boundary Force Accumulation

Provides a way to report values for force and impulse in DEM particle collisions, taken from the related field functions. Select Reports > New Report > Lagrangian > DEM Force or (for Average Moment) DEM Moment.

Average Force: Activates the Average DEM Total Force field function. Required for the DEM Force report and the DEM Moment report.
Average Moment: Activates the Average DEM Total Moment field function. Required for the DEM Moment report.
Impulse: Activates the DEM Total Impulse field function.
Maximum Force: Activates the Maximum Magnitude DEM Total Force field function.

DEM Boundary Forces Reports

DEM Force: Reports the force exerted on each part due to interaction with DEM particles, including contribution from DEM particle-wall contacts. Requires activation of the Average Force property of the wall boundary. See DEM Boundary Force Accumulation.
DEM Moment: Reports the moment exerted on each part due to interaction with DEM particles, including contribution from DEM particle-wall contacts. Requires activation of both the Average Force and the Average Moment properties of the wall boundary.

DEM Boundary Forces Field Functions

Average DEM Total Force: The time-averaged force exerted on each boundary face over a time-step.
Average DEM Total Moment: The time-averaged moment produced by the contact force about each boundary face centroid over a time-step.
DEM Total Impulse: The total impulse (force integrated over time) exerted on each boundary face over a time-step.
Maximum Magnitude DEM Total Force: The maximum force exerted on each boundary face during a time-step, as determined by comparing the forces calculated in each sub-step.