Outlet

The Outlet lets water flow downstream with a prescribed flow rate. It is similar to the Pump, except that water only flows down, by gravity.

When PID controlled, the Outlet must point towards the controlled Basin in terms of links.

1 Tables

1.1 Static

column	type	unit	restriction
node_id	Int32	-
control_state	String	-	(optional)
active	Bool	-	(optional, default true)
flow_rate	Float64	$^3/$	non-negative
min_flow_rate	Float64	$^3/$	(optional, default 0.0)
max_flow_rate	Float64	$^3/$	(optional)
min_upstream_level	Float64	\(\text{m}\)	(optional)
max_downstream_level	Float64	\(\text{m}\)	(optional)

1.2 Time

This table is the transient form of the Outlet table. With this all parameters can be updated over time. In between the given times the flow_rate is interpolated linearly, and outside the flow rate is constant given by the nearest time value. Note that a node_id can be either in this table or in the static one, but not both.

column	type	unit	restriction
node_id	Int32	-
time	DateTime	-
flow_rate	Float64	$^3/$	non-negative
min_flow_rate	Float64	$^3/$	(optional, default 0.0)
max_flow_rate	Float64	$^3/$	(optional)
min_upstream_level	Float64	\(\text{m}\)	(optional)
max_downstream_level	Float64	\(\text{m}\)	(optional)

2 Equations

The Outlet is very similar to the Pump, but it has an extra reduction factor for physical constraints:

\[ Q = \mathrm{clamp}(\phi Q_\text{set}, Q_{\min}, Q_{\max}) \]

• \(Q\) is the realized Outlet flow rate.
• \(Q_\text{set}\) is the Outlet’s target flow_rate.
• \(Q_{\min}\) and \(Q_{\max}\) are the Outlet min_flow_rate and max_flow_rate.
• \(\phi\) is the reduction factor, which smoothly reduces flow based on all of these criteria:
  • The upstream volume is below \(10 m^3\).
  • The upstream level is less than \(0.02 m\) above the downstream level.
  • The upstream level is below min_upstream_level + \(0.02 m\)
  • The downstream level is above max_downstream_level - \(0.02 m\)