09-11-2018 04:16 AM - edited 09-11-2018 04:17 AM
Hello,
In my results, I always get unrealistic value for massflow at t=0s
It makes my charts not proper.
For fixing it, I wanted to create a postprocessing value of the desired massflow by restricting it between 1 and 50 s
restrict(q1@QB,1,50)
But doing that, the expression becomes red, and also the the postprocessing variable is not available as the run is over
I dont understand why it doesn't work since the plot of q1@QB works
It runs under v15
(By the way, is it possible to enforce an unity in a postprocessing variable, instead of [null]?)
Thanks for any tip
Maxime
Solved! Go to Solution.
09-11-2018 04:36 AM
Hi,
the "unrealistic" result that you get in the very first time steps is due to a non-optimal guess of the initial values. Usually, by providing better guesses the problem should be solved. You can try to reach an equilibrium point and sue the "set final values..." option to force the initial values of the system state variables to equilibrium.
Regarding the restrict(a,t1,t2) function, I understand that the time interval that you provide in the expression must be a subset of the simulation time. In your case, t2 should be strictly less than 50 (for example: restrict(q1@QB,1,49.99)).
Starting from v16, it is possible to assign a unit of measurement to post processed variables.
Cheers,
FedericoC
09-11-2018 04:38 AM
09-11-2018 04:39 AM
09-11-2018 04:47 AM
Hello @FedericoC
Ok the problem was that my final time in the subset wasn't strictly less than my final time value
Now it works perfect!
Great
Thank you