The areas of the aquifer(s) with pronounced three-dimensional flow are often of a localised nature (or usually have a relatively small extent). It is usually difficult to define meaningful boundary conditions for small-scale models that are not influenced by the local flow pattern. In the case of three-dimensional models, enlarging the models to meaningful model boundaries is expensive in terms of storage space, clarity and computing time.

The most elegant solution in these cases is a large-scale 2D model with a 3D sub-area.

The automatic mesh generation described above can also be used here. The only additional information required is the input of one or more closed area edges using node numbers (3DRA). The programme now recognises the 2D elements within the 3D area and automatically projects the corresponding elements into the depth.

Transition from 2D area to 3D area