forked from lijiext/lammps
69 lines
2.3 KiB
HTML
69 lines
2.3 KiB
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<CENTER><A HREF = "http://lammps.sandia.gov">LAMMPS WWW Site</A> - <A HREF = "Manual.html">LAMMPS Documentation</A> - <A HREF = "Section_commands.html#comm">LAMMPS Commands</A>
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</CENTER>
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<HR>
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<H3>pair_style sph/idealgas command
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</H3>
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<P><B>Syntax:</B>
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</P>
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<PRE>pair_style sph/idealgas
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</PRE>
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<P><B>Examples:</B>
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</P>
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<P>pair_style sph/idealgas
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pair_coeff * * 1.0 2.4
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</P>
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<P><B>Description:</B>
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</P>
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<P>The sph/idealgas style computes pressure forces between particles according to the ideal gas equation of state,
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\begin<I>equation</I>
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p = (\gamma - 1) \rho e,
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\end<I>equation</I>
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where $\gamma=1.4$ is the heat capacity ratio, $\rho$ is the local density, and $e$ is the internal energy per unit mass. This pair style also computes Monaghan's artificial viscosity to prevent particles from interpentrating (Monaghan1983).
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</P>
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<P>The following coefficients must be defined for each pair of atoms
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types via the <A HREF = "pair_coeff.html">pair_coeff</A> command as in the examples
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above.
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</P>
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<P>nu artificial viscosity (no units)
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h kernel function cutoff (distance units)
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</P>
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<HR>
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<P><B>Mixing, shift, table, tail correction, restart, rRESPA info</B>:
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</P>
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<P>These pair styles do not support mixing. Thus, coefficients for all
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I,J pairs must be specified explicitly.
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</P>
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<P>This style does not write information to <A HREF = "restart.html">binary restart
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files</A>, so pair_style and pair_coeff commands do need
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to be specified in an input script that reads a restart file.
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</P>
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<P>These styles can only be used via the <I>pair</I> keyword of the <A HREF = "run_style.html">run_style
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respa</A> command. They do not support the <I>inner</I>,
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<I>middle</I>, <I>outer</I> keywords.
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</P>
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<P><B>Restrictions:</B>
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</P>
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<P>The <I>pair sph/idealgas</I> style is part of the "USER-SPH" package. It is
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only enabled if LAMMPS was built with that package (which it is by
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default). See the <A HREF = "Section_start.html#2_3">Making LAMMPS</A> section for
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more info.
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</P>
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<P><B>Related commands:</B>
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</P>
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<P><A HREF = "pair_coeff.html">pair_coeff</A>, pair_sph/rhosum
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</P>
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<P><B>Default:</B> none
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</P>
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<P><B>(Monaghan1983)</B> J. J. Monaghan and R. A. Gingold, “Shock simulation by the particle method SPH,” Journal of Computational Physics, vol. 52, no. 2, pp. 374-389, Nov. 1983.
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</P>
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</HTML>
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