74 lines
2.1 KiB
ReStructuredText
74 lines
2.1 KiB
ReStructuredText
.. index:: fix smd/integrate\_ulsph
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fix smd/integrate\_ulsph command
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================================
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Syntax
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""""""
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.. parsed-literal::
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fix ID group-ID smd/integrate_ulsph keyword
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* ID, group-ID are documented in :doc:`fix <fix>` command
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* smd/integrate\_ulsph = style name of this fix command
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* zero or more keyword/value pairs may be appended
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* keyword = adjust\_radius or limit\_velocity
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adjust\_radius values = adjust\_radius\_factor min\_nn max\_nn
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adjust\_radius\_factor = factor which scale the smooth/kernel radius
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min\_nn = minimum number of neighbors
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max\_nn = maximum number of neighbors
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limit\_velocity values = max\_velocity
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max\_velocity = maximum allowed velocity.
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Examples
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""""""""
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.. parsed-literal::
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fix 1 all smd/integrate_ulsph adjust_radius 1.02 25 50
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fix 1 all smd/integrate_ulsph limit_velocity 1000
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Description
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"""""""""""
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The fix performs explicit time integration for particles which
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interact with the updated Lagrangian SPH pair style.
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See `this PDF guide <PDF/SMD_LAMMPS_userguide.pdf>`_ to using Smooth Mach
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Dynamics in LAMMPS.
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The *adjust\_radius* keyword activates dynamic adjustment of the
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per-particle SPH smoothing kernel radius such that the number of
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neighbors per particles remains within the interval *min\_nn* to
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*max\_nn*. The parameter *adjust\_radius\_factor* determines the amount
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of adjustment per timestep. Typical values are *adjust\_radius\_factor*
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=1.02, *min\_nn* =15, and *max\_nn* =20.
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The *limit\_velocity* keyword will control the velocity, scaling the norm of
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the velocity vector to max\_vel in case it exceeds this velocity limit.
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**Restart, fix\_modify, output, run start/stop, minimize info:**
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Currently, no part of USER-SMD supports restarting nor
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minimization. This fix has no outputs.
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Restrictions
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""""""""""""
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This fix is part of the USER-SMD package. It is only enabled if
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LAMMPS was built with that package. See the :doc:`Build package <Build_package>` doc page for more info.
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**Related commands:** none
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**Default:** none
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.. _lws: http://lammps.sandia.gov
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.. _ld: Manual.html
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.. _lc: Commands_all.html
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