Syntax:
fix id group massflow/mesh mesh mesh-ID vec_side vx vy vz keyword value ...
count value = once or multiple once = count particles only once multiple = allow particles to be counted multiple times
Examples:
fix mass all massflow/mesh mesh inface vec_side 0. 0. -1.
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 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 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 .
This fix computes a per-atom vector (the marker) which can be accessed by various output commands. . 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. .
Restrictions:
Currently, this feature does not support multi-sphere particles. The fix mesh/surface has to define a planar surface.
Related commands:
compute nparticles/tracer/region
Default:
count = multiple