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Storage equation


\begin{displaymath}
\rho \; co \; \dot{p} =
k_p ( \frac{\partial^2 p}{\partial...
...}{\partial {x_3}^2} ) -
\frac{\partial v_i}{\partial x_i} + f
\end{displaymath}

Primary unknown is the groundflow_pressure p. Further notation: $\rho$ group_groundflow_density; co group_groundflow_compressibility; kp group_groundflow_permeability; xi space coordinate; vi material velocity (if present); f force_element_volume (pressure source). The equation is given for space coordinates following material velocities vi (if present).

The groundflow velocities (see groundflow_velocity) follow from:

\begin{displaymath}
{v_i}^{{\rm g}} = - k_p \frac{\partial p}{\partial x_i}
\end{displaymath}

In case of gravity, the initial nodal pressures should be initialized in the pressure part of the node_dof records, and the gravity force should be included in the pressure part of the force_element_volume record.



root
1998-11-16