83 lines
2.3 KiB
ReStructuredText
83 lines
2.3 KiB
ReStructuredText
.. index:: compute erotate/asphere
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compute erotate/asphere command
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===============================
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Syntax
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""""""
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.. code-block:: LAMMPS
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compute ID group-ID erotate/asphere
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* ID, group-ID are documented in :doc:`compute <compute>` command
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* erotate/asphere = style name of this compute command
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Examples
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""""""""
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.. code-block:: LAMMPS
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compute 1 all erotate/asphere
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Description
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"""""""""""
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Define a computation that calculates the rotational kinetic energy of
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a group of aspherical particles. The aspherical particles can be
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ellipsoids, or line segments, or triangles. See the
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:doc:`atom_style <atom_style>` and :doc:`read_data <read_data>` commands
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for descriptions of these options.
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For all 3 types of particles, the rotational kinetic energy is
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computed as :math:`\frac12 I \omega^2`, where :math:`I` is the inertia tensor
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for the aspherical particle and :math:`\omega` is its angular velocity, which
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is computed from its angular momentum if needed.
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.. note::
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For :doc:`2d models <dimension>`, ellipsoidal particles are
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treated as ellipsoids, not ellipses, meaning their moments of inertia
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will be the same as in 3d.
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Output info
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"""""""""""
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This compute calculates a global scalar (the KE). This value can be
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used by any command that uses a global scalar value from a compute as
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input. See the :doc:`Howto output <Howto_output>` page for an
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overview of LAMMPS output options.
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The scalar value calculated by this compute is "extensive". The
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scalar value will be in energy :doc:`units <units>`.
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Restrictions
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""""""""""""
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This compute requires that ellipsoidal particles atoms store a shape
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and quaternion orientation and angular momentum as defined by the
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:doc:`atom_style ellipsoid <atom_style>` command.
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This compute requires that line segment particles atoms store a length
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and orientation and angular velocity as defined by the :doc:`atom_style line <atom_style>` command.
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This compute requires that triangular particles atoms store a size and
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shape and quaternion orientation and angular momentum as defined by
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the :doc:`atom_style tri <atom_style>` command.
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All particles in the group must be of finite size. They cannot be point
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particles.
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Related commands
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""""""""""""""""
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none
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:doc:`compute erotate/sphere <compute_erotate_sphere>`
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Default
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"""""""
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none
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