"LIGGGHTS WWW Site"_liws - "LAMMPS WWW Site"_lws - "LIGGGHTS Documentation"_ld - "LIGGGHTS Commands"_lc :c

:link(liws,http://www.cfdem.com)
:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Section_commands.html#comm)

:line

fix massflow/mesh command :h3

[Syntax:]

fix id group massflow/mesh mesh mesh-ID vec_side vx vy vz keyword value ... :pre

ID, group-ID are documented in "fix"_fix.html command :ulb,l
massflow/mesh = style name of this fix command   :l
mesh = obligatory keyword :l
mesh-ID = ID of a "fix mesh/surface"_fix_mesh_surface.html command :l
vec_side = obligatory keyword :l
vx, vy, vz = vector components defining the "outside" of the mesh :l
zero or more keyword/value pairs may be appended to args :l
keyword = {count} :l
  {count} value = {once} or {multiple}
    once = count particles only once
    multiple = allow particles to be counted multiple times :pre

:ule

[Examples:]

fix mass all massflow/mesh mesh inface vec_side 0. 0. -1. :pre

[LIGGGHTS vs. LAMMPS Info:]

This LIGGGHTS command is not available in LAMMPS.

[Description:]

Fix massflow/mesh tracks how many particles penetrate through a mesh surface,
as defined by a "fix mesh/surface"_fix_mesh_surface.html command.
It counts the total number of particles and the associated mass. Only particles
part of {group} are eligible for counting.

Particles are counted if they cross from the inner side of the mesh to the outer
side of the mesh, where the outer side is defined by keyword {vec_side}. Note
that the vector defined by {vec_side} does not necessarily have to be 
perpendicular to the mesh face. The following restrictions apply: (i) the
"fix mesh/surface"_fix_mesh_surface.html has to be planar, the vector defined 
by {vec_side} may not lie inside the mesh plane. 

When {count} = once, then each particle is only counted once, for {count} = multiple
a particle contributes to number and mass count each time it crosses the mesh face.
This can happen e.g. in the case of periodic boundary conditions or in re-circulating
flow conditions.

[Restart, fix_modify, output, run start/stop, minimize info:]

Information about this fix is written to "binary restart files"_restart.html .

This fix computes a per-atom vector (the marker) which can be accessed by
various "output commands"_Section_howto.html#howto_15. . 
This fix also computes a global vector of length 4. The first vector component 
is equal to the total mass which has crosses the mesh surface, the second vector 
components indicates the particle count. The third vector component 
is equal to the total mass which has crosses the mesh surface since the last output 
divived by the time since the last output (i.e. the mass flow rate), the fourth vector 
components indicates the particle count since the last output divived by the time
since the last output (i.e. the mass flow rate). This vector
can also be accessed by various "output commands"_Section_howto.html#howto_15. . 

[Restrictions:] 

Currently, this feature does not support multi-sphere particles.
The "fix mesh/surface"_fix_mesh_surface.html has to define a planar surface.

[Related commands:]

"compute nparticles/tracer/region"_compute_nparticles_tracer_region.html 

[Default:] 

{count} = multiple
