HydroGeoSphere/Simulation Control Guidelines

Once the grid generation step is completed, the preprocessor generates a set of data for a default problem by assuming saturated, steady-state flow in a non-fractured, homogeneous porous medium. The porous medium properties for the default problem, which are hardwired in the code, are listed in Table 5.5. By default, the finite-element approach is used and a transport simulation is not done. If the default problem setup and material properties are acceptable, it is likely that the only additional data required to complete the definition of the problem are some flow boundary conditions, which can be assigned as described in Section 5.7.

Transient flow

Causes HydroGeoSphere to perform a time-stepping, transient flow solution.

• • •

Unsaturated

Causes HydroGeoSphere to perform a variably-saturated flow solution.

• • •

Do transport

Causes HydroGeoSphere to perform a transport solution.

• • •

If surface loading with hydromechanical coupling is required, you must issue the following instruction:

Surface loading

Causes HydroGeoSphere to consider surface loading with hydromechanical coupling.

• • •

The following instructions are used to define the behaviour of the Travel Time Probability Package described in Section 2.9.

Travel time PDF

Defines if a travel time PDF computation is to be performed.

• • •

Travel time CDF

Defines if a travel time CDF computation is to be performed.

• • •

Travel time PDF from CDF

Defines if the travel time PDF must be deduced from the CDF at observation points.

• • •

Mean age

Defines if a mean age/mean life expectancy computation is to be performed.

• • •

Backward-in-time

Defines if flow is to be reversed (backward transport solution).

• • •

Evaluate capture zone

Defines if an outlet capture zone is to be evaluated.

• • •

Species attribution

Defines the species number (absolutely necessary in the case of multi-species transport).

• • •

These instructions are of general interest:

Y vertical

Causes HydroGeoSphere to assume that the y-coordinate points in the vertical direction (i.e. instead of the z-coordinate).

This instruction does not switch coordinates, but merely cause HydroGeoSphere to use the y-coordinate of a node to calculate the total hydraulic head (pressure + elevation) for variably-saturated simulations. It is intended to be used for variably-saturated flow problems when using triangular prism elements, when one wants to have the triangular mesh (which is defined in the xy-plane) to be oriented along the vertical direction.

• • •

Data check only

Causes HydroGeoSphere to halt execution after reading all data files, initializing arrays etc. but prior to the start of the solution procedure.

This can be useful for very large problems, where it is desirable to make sure that all the input is correct before actually doing the simulation.

• • •