forked from lijiext/lammps
56 lines
1.7 KiB
Plaintext
56 lines
1.7 KiB
Plaintext
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"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 smd/adjust_dt command :h3
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[Syntax:]
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fix ID group-ID smd/adjust_dt arg :pre
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ID, group-ID are documented in "fix"_fix.html command :ulb,l
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smd/adjust_dt = style name of this fix command :l
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arg = {s_fact} :l
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{s_fact} = safety factor :pre
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:ule
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[Examples:]
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fix 1 all smd/adjust_dt 0.1 :pre
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[Description:]
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The fix calculates a new stable time increment for use with the SMD time integrators.
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The stable time increment is based on multiple conditions. For the SPH pair styles, a
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CFL criterion (Courant, Friedrichs & Lewy, 1928) is evaluated, which determines the the speed of
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sound cannot propagate further than a typical spacing between particles within a single time step to ensure
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no information is lost. For the contact pair styles, a linear analysis of the pair potential determines a
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stable maximum time step.
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This fix inquires the minimum stable time increment across all particles contained in the group for which this
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fix is defined. An additional safety factor {s_fact} is applied to the time increment.
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See "this PDF guide"_USER/smd/SMD_LAMMPS_userguide.pdf to use Smooth Mach Dynamics in LAMMPS.
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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 minimization.
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[Restrictions:]
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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 "Making LAMMPS"_Section_start.html#start_3
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section for more info.
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[Related commands:]
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"smd/tlsph_dt"_compute_smd_tlsph_dt.html
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[Default:] none
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