Junction#

module wntr.network.elements

class Junction[source]#

Bases: Node

Junction class, inherited from Node.

Junctions are the nodes that contain demand, emitters, and water quality sources.

Constructor

This class is intended to be instantiated through the add_junction() method. Direct creation through the constructor is highly discouraged.

Parameters:

name (string) – Name of the junction.
wn (WaterNetworkModel) – WaterNetworkModel object the junction will belong to

Attributes

`name`	The name of the node (read only)
`node_type`	`"Junction"` (read only)
`base_demand`	Get the base_value of the first demand in the demand_timeseries_list.
`demand_timeseries_list`	list of demand patterns and base multipliers
`elevation`	elevation of the junction
`coordinates`	The node coordinates, (x,y)
`emitter_coefficient`	if not None, then activate an emitter with the specified coefficient
`initial_quality`	The initial quality (concentration) at the node
`minimum_pressure`	The minimum pressure attribute is used for pressure-dependent demand simulations.
`required_pressure`	The required pressure attribute is used for pressure-dependent demand simulations.
`pressure_exponent`	The pressure exponent attribute is used for pressure-dependent demand simulations.
`tag`	A tag or label for the node

Read-only simulation results

`demand`	(read-only) the current simulation demand at the node (actual demand)
`head`	(read-only) the current simulation head at the node (total head)
`pressure`	(read-only) the current simulation pressure at the node
`quality`	(read-only) the current simulation quality at the node
`leak_demand`	(read-only) the current simulation leak demand at the node
`leak_status`	(read-only) the current simulation leak status at the node
`leak_area`	(read-only) the current simulation leak area at the node
`leak_discharge_coeff`	(read-only) the current simulation leak discharge coefficient

__init__(name, wn)[source]#

add_demand(base, pattern_name, category=None)[source]#

Add a new demand entry to the Junction

Parameters:

base (float) – The base demand value for this new entry
pattern_name (str or None) – The name of the pattern to use or None for a constant value
category (str, optional) – A category name for this demand

add_fire_fighting_demand(wn, fire_flow_demand, fire_start, fire_end, pattern_name=None)[source]#

Add a new fire flow demand entry to the Junction

Parameters:

wn (WaterNetworkModel) – Water network model
fire_flow_demand (float) – Fire flow demand
fire_start (int) – Start time of the fire flow in seconds.
fire_end (int) – End time of the fire flow in seconds.
pattern_name (str or None) – Pattern name. If pattern name is None, the pattern name is assigned to junction name + ‘_fire’

add_leak(wn, area, discharge_coeff=0.75, start_time=None, end_time=None)[source]#

Add a leak control to the water network model

Leaks are modeled by:

Q = discharge_coeff*area*sqrt(2*g*h)

where:: Q is the volumetric flow rate of water out of the leak g is the acceleration due to gravity h is the gauge head at the junction, P_g/(rho*g); Note that this is not the hydraulic head (P_g + elevation)

Parameters:

wn (WaterNetworkModel) – Water network model containing the junction with the leak. This information is needed because the WaterNetworkModel object stores all controls, including when the leak starts and stops.
area (float) – Area of the leak in m^2.
discharge_coeff (float) – Leak discharge coefficient; Takes on values between 0 and 1.
start_time (int) – Start time of the leak in seconds. If the start_time is None, it is assumed that an external control will be used to start the leak (otherwise, the leak will not start).
end_time (int) – Time at which the leak is fixed in seconds. If the end_time is None, it is assumed that an external control will be used to end the leak (otherwise, the leak will not end).

remove_fire_fighting_demand(wn)[source]#

Removes a fire flow demand entry to the Junction

Parameters:: wn (WaterNetworkModel) – Water network model

remove_leak(wn)[source]#

Remove a leak control from the water network model

Parameters:: wn (WaterNetworkModel) – Water network model

to_dict()#: Dictionary representation of the node

to_ref()#

property base_demand#

Get the base_value of the first demand in the demand_timeseries_list.

This is a read-only property.

property coordinates#

The node coordinates, (x,y)

Type:: tuple

property demand#

(read-only) the current simulation demand at the node (actual demand)

Type:: float

property demand_timeseries_list#

list of demand patterns and base multipliers

Type:: Demands

property elevation#

elevation of the junction

Type:: float

property emitter_coefficient#

if not None, then activate an emitter with the specified coefficient

Type:: float

property head#

(read-only) the current simulation head at the node (total head)

Type:: float

property initial_quality#

The initial quality (concentration) at the node

Type:: float

property leak_area#

(read-only) the current simulation leak area at the node

Type:: float

property leak_demand#

(read-only) the current simulation leak demand at the node

Type:: float

property leak_discharge_coeff#

(read-only) the current simulation leak discharge coefficient

Type:: float

property leak_status#

(read-only) the current simulation leak status at the node

Type:: bool

property minimum_pressure#

The minimum pressure attribute is used for pressure-dependent demand simulations. Below this pressure, the junction will not receive any water. If set to None, the global value in wn.options.hydraulic.minimum_pressure is used.

Type:: float

property name#

The name of the node (read only)

Type:: str

property node_type#

"Junction" (read only)

Type:: str

property nominal_pressure#: deprecated - use required pressure

property pressure#

(read-only) the current simulation pressure at the node

Type:: float

property pressure_exponent#

The pressure exponent attribute is used for pressure-dependent demand simulations. If set to None, the global value in wn.options.hydraulic.pressure_exponent is used.

Type:: float

property quality#

(read-only) the current simulation quality at the node

Type:: float

property required_pressure#

The required pressure attribute is used for pressure-dependent demand simulations. This is the lowest pressure at which the junction receives the full requested demand. If set to None, the global value in wn.options.hydraulic.required_pressure is used.

Type:: float

property tag#

A tag or label for the node

Type:: str