.. index:: fix eos/cv

fix eos/cv command
==================

Syntax
""""""

.. parsed-literal::

   fix ID group-ID eos/cv cv

* ID, group-ID are documented in :doc:`fix <fix>` command
* eos/cv = style name of this fix command
* cv = constant-volume heat capacity (energy/temperature units)

Examples
""""""""

.. code-block:: LAMMPS

   fix 1 all eos/cv 0.01

Description
"""""""""""

Fix *eos/cv* applies a mesoparticle equation of state to relate the
particle internal energy (:math:`u_i`) to the particle internal temperature
(:math:`\theta_i`).  The *eos/cv* mesoparticle equation of state requires
the constant-volume heat capacity, and is defined as follows:

.. math::

   u_{i} = u^{mech}_{i} + u^{cond}_{i} = C_{V} \theta_{i}

where :math:`C_V` is the constant-volume heat capacity, :math:`u^{cond}`
is the internal conductive energy, and :math:`u^{mech}` is the internal
mechanical energy.  Note that alternative definitions of the mesoparticle
equation of state are possible.

----------

Restrictions
""""""""""""

This command is part of the USER-DPD package.  It is only enabled if
LAMMPS was built with that package.  See the :doc:`Build package <Build_package>` doc page for more info.

This command also requires use of the :doc:`atom_style dpd <atom_style>`
command.

Related commands
""""""""""""""""

:doc:`fix shardlow <fix_shardlow>`, :doc:`pair dpd/fdt <pair_dpd_fdt>`

**Default:** none

----------

.. _Larentzos4:

**(Larentzos)** J.P. Larentzos, J.K. Brennan, J.D. Moore, and
W.D. Mattson, "LAMMPS Implementation of Constant Energy Dissipative
Particle Dynamics (DPD-E)", ARL-TR-6863, U.S. Army Research
Laboratory, Aberdeen Proving Ground, MD (2014).
