pair_style sph/idealgas command
Accelerator Variants: sph/idealgas/omp
Syntax
pair_style sph/idealgas
Examples
pair_style sph/idealgas
pair_coeff * * 1.0 2.4
Description
The sph/idealgas style computes pressure forces between particles according to the ideal gas equation of state:
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 interpenetrating (Monaghan).
See the Howto sph page for an introduction to using SPH in LAMMPS.
The following coefficients must be defined for each pair of atoms types via the pair_coeff command as in the examples above.
\(\nu\) artificial viscosity (no units)
h kernel function cutoff (distance units)
Styles with a gpu, intel, kk, omp, or opt suffix are functionally the same as the corresponding style without the suffix. They have been optimized to run faster, depending on your available hardware, as discussed on the Accelerator packages page. The accelerated styles take the same arguments and should produce the same results, except for round-off and precision issues.
These accelerated styles are part of the GPU, INTEL, KOKKOS, OPENMP, and OPT packages, respectively. They are only enabled if LAMMPS was built with those packages. See the Build package page for more info.
You can specify the accelerated styles explicitly in your input script by including their suffix, or you can use the -suffix command-line switch when you invoke LAMMPS, or you can use the suffix command in your input script.
See the Accelerator packages page for more instructions on how to use the accelerated styles effectively.
Mixing, shift, table, tail correction, restart, rRESPA info
This style does not support mixing. Thus, coefficients for all I,J pairs must be specified explicitly.
This style does not support the pair_modify shift, table, and tail options.
This style does not write information to binary restart files. Thus, you need to re-specify the pair_style and pair_coeff commands in an input script that reads a restart file.
This style can only be used via the pair keyword of the run_style respa command. It does not support the inner, middle, outer keywords.
Restrictions
This pair style is part of the SPH package. It is only enabled if LAMMPS was built with that package. See the Build package page for more info.
Default
none
(Monaghan) Monaghan and Gingold, Journal of Computational Physics, 52, 374-389 (1983).