Pump formula (Water Overlay): Difference between revisions

Revision as of 14:09, 15 April 2019

Pumps are hydraulic structures can pump water from areas with a lower water level to areas with a higher water level.

The amount flowing in or out of inlets is calculated for the cell the inlet resides on.

Case 1: Inlet: When calculating inlets, first the capacities are calculated.

If a lower threshold Tl is defined:

   Qlth = max( 0 , Tl,t - wt )

If a positive Inlet q is defined:

   Qt = Δt * qt

If a capacity Qtotal is defined:

   Qc = Qtotal- ΣQ0..t-1

After calculating the capacities, the actual water inflow is calculated. If any of the terms are undefined, they are not included.

   Δw = max( 0 , min( Qlth , Qt , Qc ) ) / A

Case 2 Outlets: When calculating outlets, first the capacities are calculated.

If an upper threshold Tu is defined:

   Quth = min( 0 , Tu - wt )

If a negative Inlet q is defined:

   Qt = Δt * qt

If a capacity Qtotal is defined:

   Qc = -Qtotal - ΣQ0..t-1

After calculating the capacities, the actual water ouflow is calculated. If any of the terms are undefined, they are not included.

   Δw = min( 0 , max( Quth , Qt , Qc) ) / A

Where:

   wt = The water level on at time t, relative to datum.
   Tl,t = The LOWER_THRESHOLD attribute of the inlet at time t.
   Tu,t = The UPPER_THRESHOLD attribute of the inlet at time t.
   qt = INLET_Q attribute at time t.
   Δt = Computational timestep.
   Qtotal = The INLET_CAPACITY attribute of the inlet.
   Q0..n = The calculated previous amounts of flow.
   Qlth = The amount of water inflow desired based on the inlet's LOWER_THRESHOLD attribute.
   Quth = The amount of water outflow desired based on the outlet's UPPER_THRESHOLD attribute.
   Qt = The amount of water inflow (or outflow when negative) possible based on the INLET_Q attribute and timestep Δt.
   Qc = The amount of water outflow possible based on the total capacity of the outlet.
   A = Size of the Inlet/Outlet area in m2, based on the amount of cells and cell size. Current implementation only has one cell.
   Δw = The amount of water flow which takes place.

Pump formula (Water Overlay): Difference between revisions

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@@ Line 1: / Line 1: @@
-The flow created by a pump is calculated based on the lowest end point of the pump.
+Pumps are hydraulic structures can pump water from areas with a lower water level to areas with a higher water level.
-: ''Δw = min( WH<sub>lower</sub> , Δt * PS )''
+The amount flowing in or out of inlets is calculated for the cell the inlet resides on.
+Case 1: Inlet:
+When calculating inlets, first the capacities are calculated.
+If a lower threshold Tl is defined:
+    Qlth = max( 0 , Tl,t - wt )
+If a positive Inlet q is defined:
+    Qt = Δt * qt
+If a capacity Qtotal is defined:
+    Qc = Qtotal- ΣQ0..t-1
+After calculating the capacities, the actual water inflow is calculated. If any of the terms are undefined, they are not included.
+    Δw = max( 0 , min( Qlth , Qt , Qc ) ) / A
+Case 2 Outlets:
+When calculating outlets, first the capacities are calculated.
+If an upper threshold Tu is defined:
+    Quth = min( 0 , Tu - wt )
+If a negative Inlet q is defined:
+    Qt = Δt * qt
+If a capacity Qtotal is defined:
+    Qc = -Qtotal - ΣQ0..t-1
+After calculating the capacities, the actual water ouflow is calculated. If any of the terms are undefined, they are not included.
+    Δw = min( 0 , max( Quth , Qt , Qc) ) / A
 Where:
-* Δw = The amount water water pumped from the lower to the higher endpoint.
-* Δt = Computational timestep.
-* WH<sub>lower</sub> = The height of the water column at the lower end of the pump, relative to the terrain.
+    wt = The water level on at time t, relative to datum.
-* PS = The [[Pump q (Water Overlay)|PUMP_Q]] of the pump.
+    Tl,t = The LOWER_THRESHOLD attribute of the inlet at time t.
-<!--* H<sub>lower</sub> = The terrain height at the lower end point, relative to {{datum}}.-->
+    Tu,t = The UPPER_THRESHOLD attribute of the inlet at time t.
+    qt = INLET_Q attribute at time t.
+    Δt = Computational timestep.
+    Qtotal = The INLET_CAPACITY attribute of the inlet.
+    Q0..n = The calculated previous amounts of flow.
+    Qlth = The amount of water inflow desired based on the inlet's LOWER_THRESHOLD attribute.
+    Quth = The amount of water outflow desired based on the outlet's UPPER_THRESHOLD attribute.
+    Qt = The amount of water inflow (or outflow when negative) possible based on the INLET_Q attribute and timestep Δt.
+    Qc = The amount of water outflow possible based on the total capacity of the outlet.
+    A = Size of the Inlet/Outlet area in m2, based on the amount of cells and cell size. Current implementation only has one cell.
+    Δw = The amount of water flow which takes place.
 ==See also==
 * [[Pump_(Water_Overlay)|Pump]].
 * [[Inlet_formula_(Water_Overlay)|Inlet formula]].
+* Moving water from higher water levels to lower water levels can be done with [[Weir_(Water_Overlay)|weirs]].
 {{Template:WaterOverlay_nav}}

Pump formula (Water Overlay): Difference between revisions

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