forked from lijiext/lammps
74 lines
2.4 KiB
Plaintext
Executable File
74 lines
2.4 KiB
Plaintext
Executable File
"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
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:link(lws,http://lammps.sandia.gov)
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:link(ld,Manual.html)
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:link(lc,Section_commands.html#comm)
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:line
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fix lb/momentum command :h3
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[Syntax:]
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fix ID group-ID lb/momentum nevery keyword values ... :pre
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ID, group-ID are documented in the "fix"_fix.html command :ulb,l
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lb/momentum = style name of this fix command :l
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nevery = adjust the momentum every this many timesteps :l
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zero or more keyword/value pairs may be appended :l
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keyword = {linear} :l
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{linear} values = xflag yflag zflag
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xflag,yflag,zflag = 0/1 to exclude/include each dimension. :pre
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:ule
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[Examples:]
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fix 1 sphere lb/momentum
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fix 1 all lb/momentum linear 1 1 0 :pre
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[Description:]
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This fix is based on the "fix momentum"_fix_momentum.html command, and
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was created to be used in place of that command, when a
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lattice-Boltzmann fluid is present.
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Zero the total linear momentum of the system, including both the atoms
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specified by group-ID and the lattice-Boltzmann fluid every nevery
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timesteps. This is accomplished by adjusting the particle velocities
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and the fluid velocities at each lattice site.
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NOTE: This fix only considers the linear momentum of the system.
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By default, the subtraction is performed for each dimension. This can
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be changed by specifying the keyword {linear}, along with a set of
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three flags set to 0/1 in order to exclude/ include the corresponding
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dimension.
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[Restart, fix_modify, output, run start/stop, minimize info:]
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No information about this fix is written to "binary restart
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files"_restart.html. None of the "fix_modify"_fix_modify.html options
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are relevant to this fix. No global or per-atom quantities are stored
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by this fix for access by various "output
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commands"_Section_howto.html#4_15. No parameter of this fix can be
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used with the {start/stop} keywords of the "run"_run.html command.
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This fix is not invoked during "energy minimization"_minimize.html.
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[Restrictions:]
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Can only be used if a lattice-Boltzmann fluid has been created via the
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"fix lb/fluid"_fix_lb_fluid.html command, and must come after this
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command.
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This fix is part of the USER-LB package. It is only enabled if LAMMPS
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was built with that package. See the "Making
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LAMMPS"_Section_start.html#start_3 section for more info.
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[Related commands:]
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"fix momentum"_fix_momentum.html, "fix lb/fluid"_fix_lb_fluid.html
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[Default:]
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Zeros the total system linear momentum in each dimension.
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