2D Boundaries

2D Boundary objects are used to define alternative boundary conditions along a section of a 2D Zone boundary, when undertaking 2D Modelling. The boundary condition defined at this object will override the 2D Zone boundary type where the boundary line and polygon boundary coincide. To pass validation, the 2D Boundary must be fully collinear with the boundary of a 2D Zone.

2D Boundary objects can be digitised directly on the GeoPlan Window. Parameters are edited in the 2D Boundary Grid Window of the Lines Grid or the 2D Boundary Property Sheet.

All of the 2D Zone boundary types are available for 2D boundaries. In addition, a boundary type of Inflow, Level or Level & Head/discharge can be assigned to a 2D boundary.

For Inflow or Level boundaries, the inflow or level hydrograph is associated with the 2D Boundary via an Inflow or Level Event, in the same way as inflows and levels are associated with nodes.

For a Level & Head/discharge boundary, a head unit flow table is associated with the boundary. A level hydrograph is also associated with the 2D Boundary, via a Level Event, which provides the depth of water at the boundary line. This depth, minus the depth at the element(s) attached to the 2D boundary line, is used to calculate the head for each 2D boundary line face. Based on the selected head unit flow table, a unit flow or flow per length is calculated on each face, which will be scaled to the face length to obtain the resulting flow entering the 2D domain.