How to monitor parameters of the particles passing the outlet?

Dear developers,
I’ve always had a need but couldn’t get it resolved. I want to monitor parameters such as the average temperature and velocity of particles coming out of the outlet surface in each time step (for example, 0.05s), can you give me some guidance?
Thank you very much.
Best wish.

I am not sure if that is entirely feasible from the GUI, but if you write a little code you could attribute a DES_USR_VAR value to particles that are near the inlet (in calc_force_dem.f is a way to start?) based on their position. Then, you use the “Monitor” tool in the GUI to look at the properties of only these particles as they would be filtered by your defined value of the DES_USR_VAR.

Thank a lot for your reply! The monitoring functions already available in the GUI cannot be realised. But I will try the second method you mentioned. Besides, the ‘inlet’ you mentioned should be ‘outlet’, right?

You could define a small box around the outlet and set up a monitor for that region. This will pick up all particles near the outlet, not just the exiters, but things like avg. temp should be reasonable. Or you could try one of the flow rate monitor types, across a plane at the outlet.

Thanks a lot for your reply. I tried this pragmatic approach you mentioned. It is simple and easy to implement but also found some problems: monitoring the box near the outlet, there is a problem of missing data. In other words, sometimes particles have crossed the box, but their information is not captured.

The monitors sample the data every monitor_dt. If monitor_dt=0.05, particles that cross the box in less than 0.05s will not be seen by the monitor. Decreasing monitor_dt should help in that case. You can also take a time average and sample the data more often than monitor_dt to compute the average:

OK, thanks. I will try do it