HydroGeoSphere/Free Drainage

Assigns a free drainage boundary condition, as described in Section 3.7.1 to nodes on all faces in the specified set. These faces should be on the surface of the domain.

The following instruction can be used as input to the Type instruction inside the Boundary condition...End instruction group to assign free drainage boundary conditions:

Free drainage

Sets the input type to be a free drainage boundary condition.

• • •

For example:

boundary condition
    type
    free drainage

    face set
    outflow

end

This example shows that a time-value table is not mandatory. However, if you wish to turn the free drainage boundary condition on or off, then this can be accomplished by including a time value table instruction:

boundary condition
    type
    free drainage

    face set
    outflow

    time value table
    0.0    1.0
    10.0   -99999.
    end

end

The value 1.0 at time zero is ignored, but the NODATA value -99999 at time 10.0 causes the boundary condition to be turned off and the nodes become unconstrained.