Loss¶
At a glance…¶
The loss node loses flow based on a provided flow-loss relationship.
[node.high_flow_loss]
type = loss
loc = 20, 30
table = 0, 0,
1000, 0,
2000, 500,
1e8, 1e7
ds_1 = node_below_loss
Node properties¶
| Property | Description |
|---|---|
| [node.?] (compulsory) | Start of node declaration. This says we are creating a node, and also defines the name of the node. Node naming conventions are discussed at . Example: [node.high_flow_loss] |
| type (compulsory) | The node type, which is “loss” in this case. type = loss |
| loc (compulsory) | The location of the node in cartesian coordinates. Example: loc = 20, 30 |
| table (optional) | Loss table defines the relationship between the upsteam flow and the loss. Refer to this page to read more about in Kalix. Example: table = 0, 0, 1000, 0, 2000, 500, 1e8, 1e7 |
| loss_rate (optional) | Loss rate override: a data reference, constant, or dynamic expression. When set, the loss is taken from this value each timestep instead of the loss table (the table, if also present, is ignored for computing loss but still shapes ordering — see below). The value is clamped between 0 and the upstream flow. Example: loss_rate = data.losses.reach_3 |
| ds_1 (optional) | Name of the downstream node. This property defines a downstream link. Inflow nodes may only have 1 downstream link. Example: ds_1 = my_other_node |
Results associated with this node¶
| Result | Description |
|---|---|
| dsflow | Total downstream flow (=ds_1) [ML] |
| usflow | Upstream flow [ML] |
| ds_1 | Downstream flow on link ds_1 [ML] |
| ds_1_order | Orders on the link ds_1 [ML] |
| loss | Amount of water lost at this node [ML] |
| loss_rate | The evaluated loss_rate expression (before clamping) [ML]. All missing values when no loss_rate property is set. |
How the node works¶
The attempted loss is determined by interpolating the provided loss table against the upstream flow — or, when the loss_rate property is set, by evaluating that expression instead. The loss actually taken is the attempted loss clamped between 0 and the upstream flow, and the remainder continues to ds_1.
loss=f(usflow) (table) or loss=loss_rate (override)
ds1=usflow−loss
A routing node can also lose water along its reach, as evaporation from a water surface whose area changes with flow: see Reach losses and dead storage. A loss node is the choice when the loss belongs at a point, or should scale with flow through a table.
Note on ordering: upstream orders are translated through the loss table in both cases. A loss_rate expression overrides how much water is actually lost, but ordering has no way to foresee an arbitrary expression's value, so it keeps using the table — supply a representative table alongside loss_rate if downstream orders should account for expected losses (with no table, ordering assumes zero loss).
References¶
None.