Multiphase Flow

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 methods. [1]

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 is reported. [1]

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. [1]

DEM04: Ball Slipping on a Rough Surface

A spherical particle is rolled on a rough surface. The angular and translation velocities are reported. [1]

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. [1]

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. [1]

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. [2]


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, January 2016.