# How to obtain outflow mass

Hi, I understand that using "flowtool" I will be able to obtain the volume of fluids excluded from the "limit box". Is there a way that I can also obtain the outflow mass or density? I know, essentially for incompressible flow, knowing the outflow volume itself immediately gives the outflow mass since the density is not changing. However, if I am dealing with compressible flow or fluid of other constitutive laws, I need also to know either the density of mass exclude to fully determine the outflow volume, mass and density.

Thanks!

## Comments

Ok, I find the way myself. Maybe good to leave a comment here. Just simply write:

for post-processing.

The saved csv file will include outflow particle mass for each step. Column "partout" is the output step, column "rhop" is the excluded particle density. Each row represents a excluded particle.