pair_style sph/taitwater/morris command — LAMMPS documentation

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# pair_style sph/taitwater/morris command

## Syntax

    pair_style sph/taitwater/morris

## Examples

    pair_style sph/taitwater/morris
    pair_coeff * * 1000.0 1430.0 1.0 2.4

## Description

The sph/taitwater/morris style computes pressure forces between SPH particles according to Tait’s equation of state:

\[p = B \biggl[\left(\frac{\rho}{\rho_0}\right)^{\gamma} - 1\biggr]\]

where \(\gamma = 7\) and \(B = c_0^2 \rho_0 / \gamma\), with \(\rho_0\) being the reference density and \(c_0\) the reference speed of sound.

This pair style also computes laminar viscosity (Morris).

See this PDF guide to using SPH in LAMMPS.

Note

Please note that the SPH PDF guide file has not been updated for many years and thus does not reflect the current syntax of the SPH package commands. For that please refer to the LAMMPS manual.

The following coefficients must be defined for each pair of atoms types via the pair_coeff command as in the examples above.

- \(\rho_0\) reference density (mass/volume units)

- \(c_0\) reference soundspeed (distance/time units)

- \(\nu\) dynamic viscosity (mass*distance/time units)

- h kernel function cutoff (distance units)

## 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.

## Related commands

pair_coeff, pair_sph/rhosum

## Default

none

(Morris) Morris, Fox, Zhu, J Comp Physics, 136, 214-226 (1997).