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MFiX 22.1 Release Announcement

Dear MFiX user,

We are pleased to announce the MFiX 22.1 release. Please download the latest version. See the release note below that highlights the changes from the previous version.

Please visit the MFS forum for any software related questions, or send administrative questions to

The MFiX Development Team

New features:

  • DEM rolling friction. The implementation corresponds to model A in Zhou et al. [1]. Inputs are rolling friction coefficients for particle-particle and particle-wall interaction.


  • Improved PIC collision damping model and added a setting to control the amount of damping.
  • Updated the thermodynamic BURCAT database.
  • Improved visibility of 2D plane regions.
  • Added a data check when reading the particle_input.dat file to make sure there is no missing column(s).
  • Added verbosity when filtering particle_input.dat file.

Notable bug fixes:

  • Fixed monitor extents (i,j,k indices) that were not consistent with BC regions.
  • Fixed rectangular internal blocks of cells that could lead to particles leave the domain in 2D DEM simulations.
  • Fixed traceback when changing resolution in procedural stl geometry.
  • Fixed VTK Gas temperature check box becoming unchecked when reloading a project in GUI.
  • Fixed problem loading images on Windows network share.
  • Fixed "File in use" error when saving under SMS mode.
  • Fixed STL region not staying selected as top level geometry after applying filter.
  • Fixed volume integral monitor having extra volume fraction.

[1] Y.C. Zhou, B.D. Wright, R.Y. Yang, B.H. Xu, A.B. Yu, "Rolling friction in the dynamic simulation of sandpile formation", Physica A: Statistical Mechanics and its Applications, Volume 269, Issues 2–4, 1999, Pages 536-553, ISSN 0378-4371,