Syntax:
fix ID group-ID lb/momentum nevery keyword values ...
linear values = xflag yflag zflag
xflag,yflag,zflag = 0/1 to exclude/include each dimension.
Examples:
fix 1 sphere lb/momentum fix 1 all lb/momentum linear 1 1 0
Description:
This fix is based on the fix momentum command, and was created to be used in place of that command, when a lattice-Boltzmann fluid is present.
Zero the total linear momentum of the system, including both the atoms specified by group-ID and the lattice-Boltzmann fluid every nevery timesteps. This is accomplished by adjusting the particle velocities and the fluid velocities at each lattice site.
NOTE: This fix only considers the linear momentum of the system.
By default, the subtraction is performed for each dimension. This can be changed by specifying the keyword linear, along with a set of three flags set to 0/1 in order to exclude/ include the corresponding dimension.
Restart, fix_modify, output, run start/stop, minimize info:
No information about this fix is written to binary restart files. None of the fix_modify options are relevant to this fix. No global 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. This fix is not invoked during energy minimization.
Restrictions:
Can only be used if a lattice-Boltzmann fluid has been created via the fix lb/fluid command, and must come after this command.
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 for more info.
Related commands:
Default:
Zeros the total system linear momentum in each dimension.