79 lines
1.8 KiB
ReStructuredText
79 lines
1.8 KiB
ReStructuredText
.. index:: compute erotate/sphere
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.. index:: compute erotate/sphere/kk
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compute erotate/sphere command
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==============================
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Accelerator Variants: *erotate/sphere/kk*
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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/sphere
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* ID, group-ID are documented in :doc:`compute <compute>` command
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* erotate/sphere = 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/sphere
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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 spherical particles.
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The rotational energy is computed as :math:`\frac12 I \omega^2`,
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where :math:`I` is the moment of inertia for a sphere and :math:`\omega`
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is the particle's angular velocity.
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.. note::
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For :doc:`2d models <dimension>`, particles are treated as
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spheres, not disks, meaning their moment of inertia will be the same
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as in 3d.
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----------
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.. include:: accel_styles.rst
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----------
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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 atoms store a radius and angular velocity
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(omega) as defined by the :doc:`atom_style sphere <atom_style>` command.
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All particles in the group must be finite-size spheres or point
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particles. They cannot be aspherical. Point particles will not
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contribute to the rotational energy.
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Related commands
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""""""""""""""""
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:doc:`compute erotate/asphere <compute_erotate_asphere>`
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Default
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"""""""
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none
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