Additional Sources of Free Energy
In some cases, the expression for the free energy can include other sources. It is possible to incorporate these by modifying
Equation 11-16
:
(11-18)
where
f
is a user-defined free energy (SI unit: J/m
3
).
The expression for the external free energy must be manually differentiated with respect to
ϕ
and then entered into the
∂
f
/∂ϕ
field. In most cases, the external free energy is zero.
