The model principle of a well is as follows:

Modelling principle of a well (R = Area of influence)

The following figure shows the discretization of a model when no well parameters are set:

FE mesh without specification of well parameters

For this example, the parameters R_i = 30.0 m, R_a = 150.0 m and C = 2.0 were specified. After confirming the dialogue, the contour points around the well resulting from the well parameters are displayed in the user interface so that the user can check the parameters and change them if necessary. These parameters are saved in the structure file and taken into account during node generation. With otherwise identical node and element generation as well as a range-wise refinement around the wells, the following discretization is obtained:

FE mesh with specification of well parameters

A comparison of the figures clearly shows the radially symmetrical distribution of the mesh nodes around the well nodes, similar to a "spider's web".

In the following vertical sections, the gradient of the water table (free surface) shows how the green line behaves similar to the cone of depression of a well due to the finer discretisation when using the well parameters (lower figure).

Vertical section without using well parameters

Vertical section with using well parameters

Stability criterion of the spatial discretization