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MFIX2015-1 Release Announcement

Dear MFIX user,

We are pleased to announce the release of the new version of MFIX (MFIX2015-1). Please download the latest version. Please see the release notes below that highlight the changes from the previous version.

Please send any software related questions to or administrative questions to

MFIX Development Team

Changes from MFIX 2014-1 (Date: 10/01/2014) to MFIX 2015-1 (Date: 04/10/2015)

New features added:

  • 2.5D model for cylindrical coordinates – A new method for pseudo two-dimensional (2.5D) simulations for cylindrical coordinates is  available by combining the benefits of Cartesian 2D and axisymmetric assumptions.
    • Li, T., Benyahia, S., Dietiker, J., Musser, J., and Sun, X. (2015), “A 2.5D computational method to simulate cylindrical fluidized beds,” Chemical Engineering Science, 123:236-246.
  • Runtime Arguments – A simulation can be passed keywords as runtime arguments to override or supplement input provided in the mfix.dat file.
  • Additional VTK Output Capabilities –
    • All simulations using Cartesian coordinates can export data in VTK file formats. Previously this file format was limited to Cartesian cut-cell based simulations.
    • Users may specify subdomains for data extraction. This allows users to save data only in regions of interest thereby reducing overall file sizes and simplifying post-processing. See the output controls section for details and mfix/tutorials/vtk_regions tutorial for an example.
    • A python script was added under the tools directory to extract ‘probe data’ from VTK data files.

Changes in existing features:

  • Arrays for the storage of particle data are automatically grown as  the number of particles in the system (or processor) increases. This removes guess work to approximate adequate array sizes. As a result, the keywords MAX_PIS and PARTICLES_FACTOR were removed.
  • New built in shapes (quadric forms) were added for greater geometrical flexibility.
  • The DES drag implementation was generalized and a new interpolation scheme was incorporated. Users must now specify which interpolation scheme is desired. See the DES keywords section for additional details.


  • Updated documents
    • MFIX User Guide [1]
    • Cartesian Grid User Guide [2]

Community Involvement:

  • A new kinetic theory model was implemented for MFIX-TFM.
    • Garzó, V., Tenneti, S., Subramaniam, S., and Hrenya, C.M. (2012). “Enskog kinetic theory for monodisperse gas-solid flows,” Journal of Fluid Mechanics, 712:129-168.

Project Metrics:

  • Change from 2014-1 Release:
    • 12 fewer files and about 3,000 lines of code added
  • 2015-1 Total count:
    • Files: 560
    • Lines: 217,316
    • Blank Lines: 34,558
    • Code Lines: 123,918
    • Comment Lines: 62,291
    • Statements: 88,854