When do I need to rebuild the solver?

MFiX
#1

Hey guys,

I have a basic question about the solver. I’m trying to build a convection-reaction TFM. For different simulations I need to change the reaction rate coefficient, inlet velocity, and etc. Do I need to rebuild the solver each time I change these parameters? Or under what conditions do I need to rebuild the solver?

Thanks,
Jack

#2

If you’re using the GUI it should warn you if you have Fortran source files that are newer than the solver executable.

Basically, you need to rebuild whenever:

  1. You are changing between DMP, SMP or serial options

  2. You modify any of the source files (the mfix “model” directory)

  3. You modify any of your user-defined FORTRAN files (UDFs). If you are modifying usr_rates.f or any file with a .f suffix, you must rebuild. The GUI should warn you before you start a run.

If you are only changing model parameters - either by using controls in the GUI or editing the mfix.dat or *.mfx file - you do not need to rebuild. These are input files that are processed by the solver at run-time.

Hope this helps,

  • Charles
#3

Thanks a lot Charles! That’s very helpful! I need to modify the UDFs so I’ll need to rebuild. I’m running things from the command line so just wanted to make sure. Thank you!

Jack

#4

By the way, is there a reason you prefer to use the command-line as opposed to GUI? As the main developer of the GUI I would like to know the reasons people are not using it. It’s intended to make things easier for you (like knowing when to rebuild the solver, etc).

– Charles

#5

The only reason I’m using command line is that I need to run 1,000 simulations in parallel on the cluster of my school. The school cluster doesn’t seem to support the MFiX GUI, and I’m not sure if I can run 1,000 simulations in parallel through MFiX GUI either.

I use the MFiX GUI to develop my code 99% of the time though, and it’s been very helpful. I’m just very new to CFD since I was not an engineering student back in college. Thanks to your efforts on developing the GUI and helping me with my basic questions I have been finishing all my projects in time so far, Charles! :slight_smile:

#6

You can use Nodeworks to run 1000s of MFIX simulations. It acts like a plugin to the GUI.

https://mfix.netl.doe.gov/doc/nodeworks/20.2.0//mfix-plugin/index.html

#7

I see. Thanks Justin! I’ll try that out.