other methods, such as the pump method "(Zhu)"_#Zhu. The pressure

correction is discussed and described in "(Strong)"_#Strong.

NOTE: For a complete example including the considerations discussed

For a complete example including the considerations discussed

above, see the examples/USER/flow_gauss directory.

NOTE: Only the flux of the atoms in group-ID will be conserved. If the

includes thermostat fixes and any constraints that hold the positions

of wall atoms fixed, such as "fix spring/self"_fix_spring_self.html.

If this fix is used in a simulation with the "rRESPA"_run_style.html

integrator, the applied acceleration must be computed and applied at the same

rRESPA level as the interactions between the flowing fluid and the obstacle.

The rRESPA level at which the acceleration is applied can be changed using

the "fix_modify"_fix_modify.html {respa} option discussed below. If the

flowing fluid and the obstacle interact through multiple interactions that are

computed at different rRESPA levels, then there must be a separate flow/gauss

fix for each level. For example, if the flowing fluid and obstacle interact

through pairwise and long-range Coulomb interactions, which are computed at

rRESPA levels 3 and 4, respectively, then there must be two separate

flow/gauss fixes, one that specifies {fix_modify respa 3} and one with

{fix_modify respa 4}.

:line

[Restart, fix_modify, output, run start/stop, minimize info:]

system's potential energy as part of "thermodynamic

output"_thermo_style.html.

The "fix_modify"_fix_modify.html {respa} option is supported by this

fix. This allows the user to set at which level of the "rRESPA"_run_style.html

integrator the fix computes and adds the external acceleration. Default is the

outermost level.

This fix computes a global scalar and a global 3-vector of forces,

which can be accessed by various "output

commands"_Section_howto.html#howto_15.  The scalar is the negative of the

Here are snapshots of example models using this command.

Corresponding input scripts can be found in examples/granregion.

Click on the images to see a bigger picture.  Movies of these

simulations are "here on the Movies page"_movies of the web site.

:link(movies,http://lammps.sandia.gov/movies.html#granregion)

simulations are "here on the Movies

page"_http://lammps.sandia.gov/movies.html#granregion of the

LAMMPS web site.

:image(JPG/gran_funnel_small.jpg,JPG/gran_funnel.png)

:image(JPG/gran_mixer_small.jpg,JPG/gran_mixer.png)