Run the another simulation using old mfix file

MFiX How to
#1

I have some queries about the simulation

  1. can I resume the simulation at whatever time I require (suppose I have a Mfix file 0-20 sec, and I want to resume from a 5-sec file and want to edit some parameter then Mfix give me the freedom to run the simulation? please let me know how.

  2. can I re-use an Mfix simulation file to run the other simulation (suppose I have the complete simulation setup file and I want to run another simulation using the previous file edit some parameters then how can I use it?

  3. can i resume my simulation from the previous time if suddenly the power off my computer?

#2
  1. Resuming the simulation requires a .RES file. The controls for restart files are in the “Output” pane (although perhaps they would make more sense in the “Run” pane).

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Normally, each .RES file saved clobbers the previous one, so you can only restart from the time the file was last saved. The variable RES_DT (“Restart/checkpoint write interval”) controls how frequently (in simulation time, not real time) this file is saved.
However there is an option to save backup RES files, setting “Restart backup count” and “Restart backup interval”. If you set these, then numbered backup copies of the .RES file will be saved to a directory called BACKUP_RES (this directory name is hard-coded and cannot be changed) - for example:

$ ls -l *RES
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 09:52 2DD.RES
-rw-r--r-- 1 cgw cgw  193536 Sep 19 09:52 2DD_DES.RES

BACKUP_RES:
total 16432
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:24 2DD.RES01
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:22 2DD.RES02
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:20 2DD.RES03
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:18 2DD.RES04
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:16 2DD.RES05
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:14 2DD.RES06
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:12 2DD.RES07
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:10 2DD.RES08
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:08 2DD.RES09
-rw-r--r-- 1 cgw cgw 1472000 Sep 19 10:07 2DD.RES10
-rw-r--r-- 1 cgw cgw  209408 Sep 19 10:24 2DD_DES.RES01
-rw-r--r-- 1 cgw cgw  209408 Sep 19 10:22 2DD_DES.RES02
-rw-r--r-- 1 cgw cgw  209408 Sep 19 10:20 2DD_DES.RES03
-rw-r--r-- 1 cgw cgw  209408 Sep 19 10:18 2DD_DES.RES04
-rw-r--r-- 1 cgw cgw  209408 Sep 19 10:16 2DD_DES.RES05
-rw-r--r-- 1 cgw cgw  209408 Sep 19 10:14 2DD_DES.RES06
-rw-r--r-- 1 cgw cgw  209408 Sep 19 10:12 2DD_DES.RES07
-rw-r--r-- 1 cgw cgw  193536 Sep 19 10:10 2DD_DES.RES08
-rw-r--r-- 1 cgw cgw  193536 Sep 19 10:08 2DD_DES.RES09
-rw-r--r-- 1 cgw cgw  193536 Sep 19 10:07 2DD_DES.RES10

Note that a restart of a DES simulation requires two files, the XXX.RES and XXX_DES.res. TFM and fluids-only simulations will have only 1 .RES file.

Unfortunately, there is no good way to tell MFiX to restart with one of the BACKUP_RES files. You will have to copy the file from the BACKUP_RES directory to the project directory and remove the number at the end. We should probably have a better way to specify which RES file to use!

  1. I’m not sure I understand this question. You can change some parameters and restart, but others are locked. EG you cannot change the geometry, add a new initial condition, etc. But you can change some velocities and other parameters, and modify things like monitors and VTK outputs. The controls which are not editable are disabled in the GUI and the controls which you can change are “unlocked”. If there’s something which is locked which you believe should be unlocked, let us know. The definitive reference is the .inc files which you can see in the model/include directory, e.g.:
!vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv!
!  Namelist: GAS_PHASE_LOCKED                                          !
!  Author: J.Musser                                   Date: 03-APR-15  !
!                                                                      !
!  Purpose: List MFIX keywords that CANNOT be edited during a run.     !
!^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^!
      NAMELIST / GAS_PHASE_LOCKED /&

      NMAX_g, SPECIES_g, SPECIES_ALIAS_g

!vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv!
!  Namelist: GAS_PHASE_UNLOCKED                                        !
!  Author: J.Musser                                   Date: 03-APR-15  !
!                                                                      !
!  Purpose: List MFIX keywords that may be edited during a run by      !
!  invoking a REFRESH.                                                 !
!^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^!
      NAMELIST / GAS_PHASE_UNLOCKED /&

      RO_g0, MU_g0, MW_AVG, MW_g, K_g0, C_pg0, DIF_g0
  1. You can resume a run any time you have a valid .RES file.
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