Possibility for parameter variation

[dholzer]

This has been mentioned before, but I'd like to add it again to this list of suggestions.

It would be incredibly useful to have the option to define one or more parameters of certain facets as "variable parameters" (e.g. the sticking factor or pumping speed, but also the temperature etc.).

Several simulations would then be run in sequence automatically, varying the parameter, using values from a list provided by the user, for example.

 

I imagine that a cheap(er) way to do this would be a command-line version of MolFlow, where the user could make several .geo files, where each file has the parameter in question changed. Then a simple batch file containing the commands to run simulations with all .geo files would do the trick...

"molflow.exe mysim_pump_001.geo"

"molflow.exe mysim_pump_025.geo"

"molflow.exe mysim_pump_150.geo"

 

[a65fc331da0c6f0160e5]

Are there updates about this issue? this would be very interesting indeed!

Probably a logfile that can be edited and reloaded could also work? Thanks

[maarton (Marton Ady)]

You can kind of achieve this, but not directly. The description below assumes that you know the use of the time-dependent mode:

Instead of running distinct simulations, you can run one with time-dependence. For the parameter(s) to vary (currently sticking factor, outgassing and opacity are supported), you use the Parameter Editor to set up the values you'd need to sweep through, and keep them constant during a long enough time so the system can reach steady state. An example is below, to sweep the sticking factor from 0 to 1 through steps of 0.2.

First the parameter 'sweep' is assigned to the two end facets:

Then the parameter is defined, through 0.5 seconds for each value, sufficient to reach steady state:

Then you define that you'd like to collect hits at the steady state part, between 0.3 and 0.5 seconds (for sticking .1), then between 0.8 and 1 seconds (for sticking .2), this is achieved by sampling 0.4s, 0.9s, ... with a time window of dt=0.2s, as below:

(Don't forget to disable "Calculate constant flow")

Then you can run the simulation in one go. To extract results you can use the Time/Time settings command to sweep through the calculated moments, or even Time-dependent tools like the Time/Pressure Evolution window to get all values at once for facets with a profile:

Attaching Molflow file:

parameter_sweep.zip