Inlet formula (Water Overlay): Difference between revisions

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If a T<sub>lower</sub> is defined:
If a T<sub>lower</sub> is defined:
: ''Q<sub>lth</sub> = max( 0 , T<sub>lower</sub> - WL<sub>surface</sub> )''
: ''Q<sub>lth</sub> = max( 0 , T<sub>lower,t</sub> - w<sub>t</sub> )''


If a q<sub>t</sub> is defined:
If a q<sub>t</sub> is defined:

Revision as of 13:05, 15 April 2019

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.

Inlets:
When calculating inlets, first the capacities are calculated.

If a Tlower is defined:

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

If a qt is defined:

Qt = Δt * qt

If a Ctotal is defined:

Qc = Qtotal- Qt-1

After calculating the capacities, the actual water inflow is calculated.

Δw = max( 0 , min( Cinthres , Cspeed , Cincap ) ) / cell
If any of the terms are undefined, they are not included.

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

If a Tlower is defined:

Coutthres = min( 0 , Tupper - WLsurface )

If a IQ is defined:

Cspeed = Δt * IQ

If a Ctotal is defined:

Coutcap = -Ctotal - Cused

After calculating the capacities, the actual water ouflow is calculated.

Δw = min( 0 , max( Coutthres , Cspeed , Coutcap) ) / cell
If any of the terms are undefined, they are not included.


After the water flow (either inflow or outflow) is computed, the capacity is updated.

Cused (new) = Cused (old) + (Δw * cell)


Where:

  • Δw = The amount of water flow which takes place.
  • Δt = Computational timestep.
  • cell = Cell size.
  • Cspeed = The amount of water inflow (or outflow when negative) possible based on the inlet's INLET_Q attribute.
  • Cincap = The amount of water inflow possible based on the total capacity of the inlet.
  • Coutcap = The amount of water outflow possible based on the total capacity of the outlet.
  • Cinthres = The amount of water inflow desired based on the inlet's LOWER_THRESHOLD attribute.
  • Coutthres = The amount of water outflow desired based on the outlet's UPPER_THRESHOLD attribute.
  • WLsurface = The water level on the surface, relative to datum.
  • Ctotal = The INLET_CAPACITY attribute of the inlet.
  • IQ = The INLET_Q attribute of the inlet.
  • Tl = The LOWER_THRESHOLD attribute of the inlet.
  • Tu = The UPPER_THRESHOLD attribute of the inlet.

See also

Template:WaterOverlay nav