forked from lijiext/lammps
49 lines
2.0 KiB
Plaintext
49 lines
2.0 KiB
Plaintext
"Higher level section"_Howto.html - "LAMMPS WWW Site"_lws - "LAMMPS
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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,Commands_all.html)
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:line
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2d simulations :h3
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Use the "dimension"_dimension.html command to specify a 2d simulation.
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Make the simulation box periodic in z via the "boundary"_boundary.html
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command. This is the default.
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If using the "create box"_create_box.html command to define a
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simulation box, set the z dimensions narrow, but finite, so that the
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create_atoms command will tile the 3d simulation box with a single z
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plane of atoms - e.g.
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"create box"_create_box.html 1 -10 10 -10 10 -0.25 0.25 :pre
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If using the "read data"_read_data.html command to read in a file of
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atom coordinates, set the "zlo zhi" values to be finite but narrow,
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similar to the create_box command settings just described. For each
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atom in the file, assign a z coordinate so it falls inside the
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z-boundaries of the box - e.g. 0.0.
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Use the "fix enforce2d"_fix_enforce2d.html command as the last
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defined fix to insure that the z-components of velocities and forces
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are zeroed out every timestep. The reason to make it the last fix is
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so that any forces induced by other fixes will be zeroed out.
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Many of the example input scripts included in the LAMMPS distribution
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are for 2d models.
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NOTE: Some models in LAMMPS treat particles as finite-size spheres, as
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opposed to point particles. See the "atom_style
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sphere"_atom_style.html and "fix nve/sphere"_fix_nve_sphere.html
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commands for details. By default, for 2d simulations, such particles
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will still be modeled as 3d spheres, not 2d discs (circles), meaning
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their moment of inertia will be that of a sphere. If you wish to
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model them as 2d discs, see the "set density/disc"_set.html command
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and the {disc} option for the "fix nve/sphere"_fix_nve_sphere.html,
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"fix nvt/sphere"_fix_nvt_sphere.html, "fix
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nph/sphere"_fix_nph_sphere.html, "fix npt/sphere"_fix_npt_sphere.html
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commands.
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