%INTEGRATION_INT_TIME%
volume and time integration of a functional with respect to a given material
This computes the integral of a functional \( f\) (
ExpressionOfIntegrand) with respect to the region \( \Omega\) identified by the material flag $MaterialTag$
\begin{align} I_{\text{Time}} = \int\limits_{t_0}^{t_{n+1}} \int\limits_{\Omega} f(t) dV dt\end{align}
by a preliminary approximation
\begin{align} I \approx \sum_{i \in P} f_i \left( t_{n+1} \right) \cdot V_i\left( t_{n+1} \right)\end{align}
and a subsequent time integration:
\begin{align} I_{\text{Time}}\left( t_{n+1} \right) = I_{\text{Time}}\left( t_{n} \right) + \left(t_{n+1}-t_{n} \right) \cdot I\end{align}
\( P\) is the set of all points with the given material flag and \( V_i\) is the volume of the i-th point.
Note: Analogous to
%INTEGRATION_BND_TIME%, a list of material flags can be used to specify the integration region. The number of flags is not limited.
Example: total turbulent dissipation of some material
For
DROPLETPHASE points the same remarks as for
%INTEGRATION_INT% apply and we obtain
\begin{align} I \approx \sum_{i \in P} f_i \left( t_{n+1} \right) \cdot n_i \left( t_{n+1} \right) \cdot V_i\left( t_{n+1} \right)\end{align}
where \( n_i\) corresponds to the multiplicity stored in
%ind_mult%.