print density in a region

Hello everyone
I am doing a simulation to check the bulk density of the particles, which is filled in a box. I want to know the bulk density or mass of the particles within the box.
How can I do this?

Forums:

LIGGGHTS® - User Forum

richti83 | Wed, 03/13/2019 - 10:55

You can use the variable mass

You can use the variable mass function or - in postprocessing - using https://www.cfdem.com/forums/paraview-filter-void-fraction-estimation
the 2nd one has the advantage of NOT taking the overlap volume into account when calculating the pure particle volume.

PPhurit | Thu, 03/14/2019 - 02:08

Primitive approach

1) Simply use [fix property/atom/tracer] to trace particles, then [compute nparticles/tracer/region] to count them.
2) In your [thermo_style] print the [n_'name of the nparticles'[3]] to print the mass of the particles in the trace region.
I'm sure this approach won't count the overlapping like @richti83 stated above.

(I'm not an associate of DCS GmbH and not a core developer of LIGGGHTS®)

Rahul Kumar | Thu, 03/14/2019 - 12:27

doubt about density

Sir
I have a doubt that whether the density entered in liggghts is solid density or bulk density?
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fix pts1 all particletemplate/multisphere 15485863 atom_type 1 density constant 2280 nspheres 4 ntry 1000000 spheres file data/particle1.multisphere scale 0.015 type 1
-------------------------------------------------------------

richti83 | Fri, 03/15/2019 - 07:08

It's solid, bulk density

It's solid, bulk density depends on material parameter like friction, cor, cohesion...

Rahul Kumar | Fri, 03/15/2019 - 08:09

variable mass function

sir can you tell the syntax for variable mass function and how to print mass on screen. I am having problem in this.
Can you give more detail about getting the mass of particle in a region in paraview.
https://www.cfdem.com/forums/paraview-filter-void-fraction-estimation
I dont know how to add this filler in paraview