forked from lijiext/lammps
95 lines
3.3 KiB
Plaintext
Executable File
95 lines
3.3 KiB
Plaintext
Executable File
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
|
|
|
|
:link(lws,http://lammps.sandia.gov)
|
|
:link(ld,Manual.html)
|
|
:link(lc,Section_commands.html#comm)
|
|
|
|
:line
|
|
|
|
fix lb/viscous command :h3
|
|
|
|
[Syntax:]
|
|
|
|
fix ID group-ID lb/viscous :pre
|
|
|
|
ID, group-ID are documented in "fix"_fix.html command
|
|
lb/viscous = style name of this fix command :ul
|
|
|
|
[Examples:]
|
|
|
|
fix 1 flow lb/viscous
|
|
|
|
[Description:]
|
|
|
|
This fix is similar to the "fix viscous"_fix_viscous.html command, and
|
|
is to be used in place of that command when a lattice-Boltzmann fluid
|
|
is present, and the user wishes to integrate the particle motion using
|
|
one of the built in LAMMPS integrators.
|
|
|
|
This fix adds a force, F = - Gamma*(velocity-fluid_velocity), to each
|
|
atom, where Gamma is the force coupling constant described in the "fix
|
|
lb/fluid"_fix_lb_fluid.html command (which applies an equal and
|
|
opposite force to the fluid).
|
|
|
|
IMPORTANT NOTE: This fix should only be used in conjunction with one
|
|
of the built in LAMMPS integrators; it should not be used with the
|
|
"fix lb/pc"_fix_lb_pc.html or "fix
|
|
lb/rigid/pc/sphere"_fix_lb_rigid_pc_sphere.html integrators, which
|
|
already include the hydrodynamic forces. These latter fixes should
|
|
only be used if the force coupling constant has been set by the user
|
|
(instead of using the default value); if the default force coupling
|
|
value is used, then this fix provides the only method for adding the
|
|
hydrodynamic forces to the particles.
|
|
|
|
:line
|
|
|
|
For further details, as well as descriptions and results of several
|
|
test runs, see "Mackay et al."_#Mackay. Please include a citation to
|
|
this paper if this fix is used in work contributing to published
|
|
research.
|
|
|
|
:line
|
|
|
|
[Restart, fix_modify, output, run start/stop, minimize info:]
|
|
|
|
As described in the "fix viscous"_fix_viscous.html documentation:
|
|
|
|
"No information about this fix is written to "binary restart
|
|
files"_restart.html. None of the "fix_modify"_fix_modify.html options
|
|
are relevant to this fix. No global or per-atom quantities are stored
|
|
by this fix for access by various "output
|
|
commands"_Section_howto.html#howto_15. No parameter of this fix can
|
|
be used with the {start/stop} keywords of the "run"_run.html command.
|
|
|
|
The forces due to this fix are imposed during an energy minimization,
|
|
invoked by the "minimize"_minimize.html command. This fix should only
|
|
be used with damped dynamics minimizers that allow for
|
|
non-conservative forces. See the "min_style"_min_style.html command
|
|
for details."
|
|
|
|
[Restrictions:]
|
|
|
|
This fix is part of the USER-LB package. It is only enabled if LAMMPS
|
|
was built with that package. See the "Making
|
|
LAMMPS"_Section_start.html#start_3 section for more info.
|
|
|
|
Can only be used if a lattice-Boltzmann fluid has been created via the
|
|
"fix lb/fluid"_fix_lb_fluid.html command, and must come after this
|
|
command.
|
|
|
|
This fix should not be used if either the "fix lb/pc"_fix_lb_pc.html
|
|
or "fix lb/rigid/pc/sphere"_fix_lb_rigid_pc_sphere.html integrator is
|
|
used.
|
|
|
|
[Related commands:]
|
|
|
|
"fix lb/fluid"_fix_lb_fluid.html, "fix lb/pc"_fix_lb_pc.html, "fix
|
|
lb/rigid/pc/sphere"_fix_lb_rigid_pc_sphere.html
|
|
|
|
[Default:] none
|
|
|
|
:line
|
|
|
|
:link(Mackay)
|
|
[(Mackay et al.)] Mackay, F. E., Ollila, S.T.T., and Denniston, C., Hydrodynamic Forces Implemented into LAMMPS through a lattice-Boltzmann fluid, Computer Physics Communications 184 (2013) 2021-2031.
|