CFD Online Discussion Forums - Get a variable at each time-step

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Get a variable at each time-step

Hello everyone,
I would like to get the mass fraction of a component in the mixture at each time-step and use that in the journal file that I have written.
In fact, I want to get mass fraction of component X, inside the journal file like physical time, time-step size etc.
The problem is that since mass fraction is a post-processing variable, I cannot use getvar in journal file.
So, I don't know how to get this variable at each time-step.
Would you please guide me if you are familiar with that?
Thanks,
Parisa

Assuming you have boundary zone "outflow1" and you want to know mass fraction of X, the following commands should be added to your jou file:

Code:

/report/surface-integrals/area-weighted-avg/

outflow1

()

X

y

X_mass_fractions.srp

y

the last y to append data, not to overwrite. The previous y - write to file - yes. Exchange y for your substance, e.g. H2O.

Probably, you can use

Code:

plot/solution

plot/solution-set/plot-to-file

(try to make it work manually, start FLUENT in terminal mode and train yourself)