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>lt</sub> = max( 0 , T<sub>lower</sub> - WL<sub>surface</sub> )'' | ||
If a I<sub>Q</sub> is defined: | If a I<sub>Q</sub> is defined: | ||
: '' | : ''Q<sub>i</sub> = Δt * I<sub>Q</sub>'' | ||
If a C<sub>total</sub> is defined: | If a C<sub>total</sub> is defined: | ||
: '' | : ''Q<sub>c</sub> = Q<sub>total</sub>''- Q<sub>t-1</sub> | ||
After calculating the capacities, the actual water inflow is calculated. | After calculating the capacities, the actual water inflow is calculated. | ||
Revision as of 13:03, 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:
- Qlt = max( 0 , Tlower - WLsurface )
If a IQ is defined:
- Qi = Δt * IQ
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.