[ghost82]

Hi,
a collegue of mine did a simulation in barracuda and he gave me files for postprocessing.
I need to calculate the mean temperature of particles exiting the reactor vs time (unsteady simulation).
I have 2 variables for temperature: "p_temp", which is the particle temperature in the eulerian frame (so I can colour cells by this variable for example) and "temperature", which is the particle temperature in the lagrangian frame (so I can colour the spherical particles by this variable for example).
For the eulerian frame I have the cells of the entire reactor (in ensight a part called "cells"), and for the lagrangian frame I have a part in ensight called "particles".

If I create a plane on the eulerian cells, near the exit of the reactor and I calculate the mean temperature of p_temp on that plane, the mean is wrong, because not all the 2d cells have particles, so cells with no particles have a temperature of 0 and the mean takes into account also these cells.

For the lagrangian part I'm not able to perform any operation, as I don't know how I can perform a mean on particles at exit.

How can I do to solve this problem?


As usual, thank you for your valuable support.

[Marina G]

Daniele,

I think that the fastest way to get the result you're looking for is to:
1. create an inside box clip for the particle part next to the exit, so that only the particles that are close to the exit are going to be in the clipped part
2. select this part and calculate the mean of "temperature" on it.

This should give you the mean temperature of only the particles that are close to the exit.
Let me know if this doesn't work for you.

Best Regards,

Marina Galvagni
CEI Software Support Engineer

[ghost82]

Hi Marina, that was one of my ideas.
I created the small box near to the exit (by selecting the particles part) which has some particles inside but when I perform the mean of "temperature" for that box it returns zero.
What can be wrong?

[Marina G]

Daniele,

I've put at the link:

https://www.transferbigfiles.com/c08...k5RoAK8rsxyPw2

a screencast where I am doing the steps described above with a Barracuda dataset, so you can see exactly each step and find if you're doing something differently.

A few things that might be going wrong:

- make sure when you create the box clip that it's an *inside* clip, and not intersect.

- make sure there actually are particles inside the box clip. You can verify this either visually (by turning all other parts off), or by calculating NodeCount on the clipped part. This will return the number of nodes ( = particles ) that are in this part

- check that your variable is defined on this clipped part (make all other parts invisible and color the clipped part by the variable. Change the palette min/max to make sure that the coloration makes sense and it's not 0 everywhere)

- Try to calculate the value manually. You can calculate the two variables

StatMomentum(Temperature, Sum)

and

NodeCount

on the clipped part. Then, calculate StatMomentum(Temperature,Sum)/NodeCount. This should return the mean value.
By calculating the two factors by hand, you may get some more insight on what is going wrong - maybe the sum of all temperatures is a number that causes overflow as it's too big?


Let me know what you find,

Marina

[ghost82]

Thank you very much Marina, now it works. My error was a choice of a wrong function to calculate the mean.
Thank you again!