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:link(lws,http://lammps.sandia.gov)
:link(ld,Manual.html)
:link(lc,Commands_all.html)

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fix smd/integrate_ulsph command :h3

[Syntax:]

fix ID group-ID smd/integrate_ulsph keyword :pre

ID, group-ID are documented in "fix"_fix.html command
smd/integrate_ulsph = style name of this fix command
zero or more keyword/value pairs may be appended
keyword = adjust_radius or limit_velocity :ul

adjust_radius values = adjust_radius_factor min_nn max_nn
      adjust_radius_factor = factor which scale the smooth/kernel radius
      min_nn = minimum number of neighbors
      max_nn = maximum number of neighbors
limit_velocity values = max_velocity
      max_velocity = maximum allowed velocity.

[Examples:]

fix 1 all smd/integrate_ulsph adjust_radius 1.02 25 50
fix 1 all smd/integrate_ulsph limit_velocity 1000 :pre

[Description:]

The fix performs explicit time integration for particles which
interact with the updated Lagrangian SPH pair style.

See "this PDF guide"_PDF/SMD_LAMMPS_userguide.pdf to using Smooth Mach
Dynamics in LAMMPS.

The {adjust_radius} keyword activates dynamic adjustment of the
per-particle SPH smoothing kernel radius such that the number of
neighbors per particles remains within the interval {min_nn} to
{max_nn}. The parameter {adjust_radius_factor} determines the amount
of adjustment per timestep. Typical values are {adjust_radius_factor}
=1.02, {min_nn} =15, and {max_nn} =20.

The {limit_velocity} keyword will control the velocity, scaling the norm of
the velocity vector to max_vel in case it exceeds this velocity limit.

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

Currently, no part of USER-SMD supports restarting nor
minimization. This fix has no outputs.

[Restrictions:]

This fix is part of the USER-SMD package.  It is only enabled if
LAMMPS was built with that package.  See the "Build
package"_Build_package.html doc page for more info.

[Related commands:] none

[Default:] none
