Inlet formula (Water Overlay): Difference between revisions

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After calculating the capacities, the actual water ouflow is calculated. If any of the terms are undefined, they are not included.
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( Q<sub>uth</sub> , Q<sub>t</sub> , Q<sub>c</sub>) ) / A''
: <math>\Delta w = \frac { min( 0 , max( Q_{uth} , Q_t, Q_c) ) } / {A}</math>


Where:
Where:

Revision as of 15:14, 4 December 2020

Inlets are hydraulic structures can pump water in and out of the project area and are connected with a water body outside the project area.

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 is defined:

If a positive inlet q Qt is defined:

If a capacity Qtotal is defined:

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,t is defined:

Quth = min( 0 , Tu,t - wt )

If a negative inlet q Qt 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.

Where:

  • Q0..n = The calculated previous amounts of flow.
  • Qlth = The desired lower water level at the inlet's location, based on the LOWER_THRESHOLD of the inlet.
  • Quth = The desired upper water level at the outlet's location, based on the outlet's UPPER_THRESHOLD of the inlet.
  • Qt = The amount of water inflow (or outflow when negative) possible based on the INLET_Q of the inlet and timestep Δt.
  • Qc = The total amount of water inflow (or outflow when negative) allowed based on the total capacity of the inlet.
  • 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.

Related

The following topics are related to this formula.

Structures
Inlet
Models
Surface model