GGU-2D-SSFLOW: Step 6: Optimise element topology (Example 1)

In principle, it is always a good idea to optimise the element topology before commencing modelling. However, in horizontal-plane systems this means that the values for aquifer base and aquifer top cannot be adapted to the new location due to the displacement of individual nodes. If the values for aquifer base and aquifer top vary within the system the program will issue a warning.

Generally, topology optimisation should always be performed after defining the potential boundary conditions, because the program does not displace nodes with potential boundary conditions during optimisation. If optimisation is carried out before defining the boundary conditions, the location of the well point in the centre may be altered.

Go to the "Mesh/Optimise" menu item and click the "Topology" button in the dialog box. After acknowledging the warning message you will see the following dialog box:

If you activate the "Adapt aq. base and aq. top" check box the values for aq. base and aq. top are adapted to the displaced nodes as well as possible during optimisation. The menu item "z / Layer boundary contours" allows you to convince yourself that the base of the aquifer no longer displays an exactly linear drop from left to right. In order to restore the exact course the values for aq. base and aq. top are defined in the next step via an interpolation mesh.