Inlet formula (Water Overlay): Difference between revisions
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* cell = Cell size. | * cell = Cell size. | ||
* C<sub>speed</sub> = The amount of water inflow (or outflow when negative) possible based on the inlet's | * C<sub>speed</sub> = The amount of water inflow (or outflow when negative) possible based on the inlet's [[Inlet q (Water Overlay)|INLET_Q]] attribute. | ||
* C<sub>incap</sub> = The amount of water inflow possible based on the total | * C<sub>incap</sub> = The amount of water inflow possible based on the total [[Inlet capacity (Water Overlay)|capacity]] of the inlet. | ||
* C<sub>outcap</sub> = The amount of water outflow possible based on the total | * C<sub>outcap</sub> = The amount of water outflow possible based on the total capacity of the outlet. | ||
* C<sub>inthres</sub> = The amount of water inflow desired based on the inlet's | * C<sub>inthres</sub> = The amount of water inflow desired based on the inlet's [[Lower threshold (Water Overlay)|LOWER_THRESHOLD]] attribute. | ||
* C<sub>outthres</sub> = The amount of water outflow desired based on the outlet's | * C<sub>outthres</sub> = The amount of water outflow desired based on the outlet's [[Upper threshold (Water Overlay)|UPPER_THRESHOLD]] attribute. | ||
* WL<sub>surface</sub> The water level on the surface, relative to | * WL<sub>surface</sub> The water level on the surface, relative to [[Datum|datum]]. | ||
* C<sub>total</sub> = The | * C<sub>total</sub> = The [[Inlet capacity (Water Overlay)|INLET_CAPACITY]] attribute of the inlet. | ||
* I<sub>Q</sub> = The | * I<sub>Q</sub> = The INLET_Q attribute of the inlet. | ||
* T<sub>lower</sub> = The | * T<sub>lower</sub> = The LOWER_THRESHOLD attribute of the inlet. | ||
* T<sub>upper</sub> = The | * T<sub>upper</sub> = The UPPER_THRESHOLD attribute of the inlet. | ||
==See also== | ==See also== | ||
Revision as of 14:07, 4 April 2019
The amount flowing in or out of inlets is calculated for the cell the inlet resides on.
When calculating inlets, first the capacities are calculated.
If a Tlower is defined:
- Cinthres = max( 0 , Tlower - WLsurface )
If a IQ is defined:
- Cspeed = Δt * IQ
If a Ctotal is defined:
- Cincap = Cused - Ctotal
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.
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.
- Tlower = The LOWER_THRESHOLD attribute of the inlet.
- Tupper = The UPPER_THRESHOLD attribute of the inlet.