fix property/set command

Syntax

fix ID group-ID property/set keywords values

  • ID, group-ID is documented in fix command.

  • property/set = style name of this fix command

  • zero or more keyword/value pairs may be appended

  • keyword = property or value or scale or region or compute_surface

property value = p-ID
  p-ID = valid ID of the fix property/atom that should be set
value values = val
  val = value to assign to the temperature or heat source of the particles (constant, equal-style or atom-style variable)
scale values = const or surface or volume
  const = do not scale value
  surface = scale value with particle surface
  volume = scale value with particle volume
region value = region-ID
  region-ID = ID of region particles must be in
compute_surface = compute-surface-ID
  compute-surface-ID = ID of a compute surface command
criteria = per-atom-variable-ID
  per-atom-variable-ID = ID of a atom-style variable

Examples

fix setheat all property/set property Temp value 320.

Description

This fix allows to set the value for a fix property/atom , such as temperature or heat source in conjunction with a fix that solves for heat transfer, such as fix heat/gran/conduction .

Keyword property expects a valid ID of the fix property/atom that should be set, and the value defined by the value keyword is set each time-step. value can either be a constant expression or refer to an equal- or atom-style variable

Keyword scale can be used to define if the property should be set to value directly, or scaled by the surface area of particle (value * radius * radius * pi), or scaled by the volume of the particle (value * radius * radius * radius * 4*pi/3).

Keywords region, compute_surface and criteria can be used to further refine the selection of particles that the operation is applied to. If the region keyword is used, the atom must be in the specified geometric region. If the compute_surface keyword is used, the atom must be on the surface of the particle bed, as defined by a compute surface command. Finally the criteria keyword allows to use any atom-style variable to define the selected particles. As soon as the variable is unequal 0 the particle is selected (except other criteria fail).

Restart, fix_modify, output, run start/stop

This fix writes no data to binary restart files . None of the fix_modify options are relevant to this fix. No global scalar or vector or per-atom quantities are stored by this fix for access by various output commands. No parameter of this fix can be used with the start/stop keywords of the run command.

Restrictions

None

Default

scale = const