Nodes¶
Points associated with reach ends and reach junctions are called nodes. Each reach has one node in each end. A node is associated with at least one reach, but an arbitrary number of reaches can be attached to a single node, defining the junction of all the reaches. A node is always present in a junction in the network.
Nodes can be volume free; then they function as simple junctions that connects two or more reaches, called a junction node. A junction node does not have any qualitative impact on the flow it passes the node
Nodes can also have a volume, as for example a manhole in a sewer, in which case the volume is considered during the calculation. When water flows through such a node, the node will usually impose additional flow resistance; the water will loose some energy while passing the node. Flow resistance and energy loss in a node is called headloss
Volume-free nodes with only one reach are called boundary nodes. In boundary nodes, a boundary condition must be specified. A boundary condition can, for example, specify a water level.
Nodes can be one of several different types:
- Junction nodes, the volume free node
- Manholes
- Basins
- Outlets
A node has a geographical (x,y) position. It can also have an identification string, which is used when inflow is to be added to the node, or attaching a structure to the node.
A node is a computational point, and contains a water level.