As part of the ECP MFIX-Exa project, CCSE is working with the National Technology Energy Laboratory
(NETL) and the University of Colorado, Boulder (CU Boulder) to improve the computational efficiency
of the newly formed MFIX-Exa code. (Movies courtesy of Erik Palmer.)
DEM01: Free Falling Particle with Wall Collision
A particle freefalls in a vacuum and collides with a wall. The
position and velocity during the three stages, free-fall, collision,
and rebound are reported. This case serves to verify the linear
spring-dashpot collision model as well as the accuracy of time-stepping
DEM02: Bouncing Particle
A particle freefalls in a vacuum and collides with a wall several times.
The resulting height the particle reaches post-collision each time
DEM03: Two Stack, Compressed Particles
Two particles are compressed, and their center positions are reported.
This serves to verify the linear spring-dashpot collision model through
the analysis of a multi-particle, enduring collision.
DEM04: Ball Slipping on a Rough Surface
A spherical particle is rolled on a rough surface. The angular and
translation velocities are reported.
DEM05: Oblique Particle Collision
Ninety-three cases of oblique particle collisions are tested
simultaneously. In each collision one particle represents a stationary
wall which the other particle strikes at an angle. The post collision
angle and angular velocity are reported for each particle. This case
serves to verify the normal and tangential components of both the
linear spring-dashpot model and Hertzian model.
DEM06: Single Particle Terminal Velocity
A particle, initially at rest, is released in a uniform flow field. The
particle's velocity increases until it reaches terminal velocity where
the gravitational forces balance the fluid-particle drag force. The
reported terminal velocity is compared to its theoretical value.
DEM07: Homogeneous Cooling System
Particles with no net flow are specified initial granular temperature
are allowed to cool over time. The granular temperature of the system
is reported over time.
1. J. Musser and A. Choudhary, "MFIX Documentation Volume 3: Verification
and Validation Manual," from
2. Peiyuan Liu, Timothy Brown, William D. Fullmer, Thomas Hauser,
and Christine Hrenya, "A Comprehensive Benchmark Suite for Simulations
of Particle Laden Flows Using the Discrete Element Method with
Performance Profiles from the Multiphase Flow with Interface
eXchanges (MFiX) Code," Technical Report NREL/TP-2C00-65637,