compute erotate/multisphere command

Syntax

compute ID group-ID erotate/multisphere general_keyword general_values

ID, group-ID are documented in compute command
erotate/multisphere = style name of this compute command
general_keywords general_values are documented in compute

Examples

compute 1 all erotate/multisphere

Description

Define a computation that calculates the rotational kinetic energy of a collection of multisphere bodies.

The rotational energy of each multisphere body is computed as

$E_{rot} = \frac{1}{2} I \omega_{body}^2$

where $I$ is the inertia tensor for the multisphere body, and $\omega_{body}$ is its angular velocity vector. Both quantities are in the frame of reference of the multisphere body, i.e. $I$ is diagonalized.

This compute automatically connects to the fix multisphere commands which defines the multisphere bodies. The group specified in the compute command is ignored. The rotational energy of all the multisphere bodies defined by the fix multisphere command in included in the calculation.

Output info:

This compute calculates a global scalar (the summed rotational energy of all the multisphere bodies). This value can be used by any command that uses a global scalar value from a compute as input. See the HowTo document on output for an overview of Aspherix® output options.

The scalar value calculated by this compute is “extensive”. The scalar value will be in energy units.

Restrictions

none

Default: none