predefined command

Warning

GPU support for this command has not been tested and may not work as expected.

Syntax

fix ID group-ID insert/stream seed seed_value distributiontemplate dist-ID general_keywords general_values stream_keywords stream_values ...

ID, group-ID are documented in fix command
insert/stream = style name of this fix command
seed = obligatory keyword
seed_value = random # seed (prime number greater 1000)
distributiontemplate = obligatory keyword
dist-ID = ID of a fix_particledistribution_discrete to be used for particle insertion
one or more general keyword/value pairs can be appended
general_keywords = verbose or nparticles or mass vel constant

verbose = yes or no
nparticles values = np or INF
  np =  number of particles to insert (positive integer)
  INF =  insert as many particles as possible
mass values = mp
  mp = mass of particles to be inserted (positive float)
  INF =  insert as many particles as possible
start value = ts
  ts = time-step at which insertion should start (positive integer larger than current time-step)
vel constant values = vx vy vz
  vx = x-velocity at insertion (velocity units)
  vy = y-velocity at insertion (velocity units)
  vz = z-velocity at insertion (velocity units)

following the general keyword/value section, one or more stream keyword/value pairs can be appended for the fix insert/stream command
stream_keywords = file or volume_fraction

file value = filename (obligatory)
  filename = name of file that contains the binary particle data
volume_fraction values = vf
  vf = particle volume fraction

Examples

fix ins all insert/stream/predefined seed 123457 distributiontemplate pdd1 nparticles 5000 vel constant 0. 0. -2. file restart/stream.data volume_fraction 0.01

Description

Reads particle distribution data from a file that was specified using the file keyword. This file can be created using the fix packing/prepare and a general guide on how to use these fixes in combination can be found here.

The volume_fraction keyword can be either set to a specific value or to “INF”. The latter case will insert the maximum particle volume fraction and the further will remove particles from the packing in order to reach the desired value. Instead of setting the volume_fraction keyword it is also possible to use the particlerate or massrate keywords of fix insert stream to achieve an appropriate insertion rate. The principle is the same, i.e. particles from the packing are removed to reach the desired rate.

The number of particles to be inserted in total can be governed either through the mass or the nparticles keyword. The former will attempt to reach the mass of the inserted particles as closely as possible, while the latter will do the same for the number of particles. Note, when using multiplespheres these numbers can be altered to become multiples of template. An output will inform you on the corresponding changes.

Restrictions

This fix only works with spheres and multiplespheres.

Default

volume_fraction = INF