V-Notch Weir flow is calculated using the following formula:
Cd = Coefficient of Discharge
vang = internal angle of the V (degrees)
g = acceleration due to gravity (9.81 m²/s)
H = height of water above weir invert
When the downstream level is above the crest level the software will use the Villemonte equation to simulate the submerged nature of the flow:
Qs = Submerged Flow Rate
Q = Free-flow rate at H
Yd = Depth downstream
H = Water Depth at point of measurement
Note: Discharge exponent of 2.5 (5/2) used for V-Notch weirs.
Angle of V - Enter the angle of the V in degrees.
Coefficient of Discharge - Enter the discharge coefficient of the weir. A default value of 0.59 is given.
Invert Level - The invert level of the Weir.
Workflow - What's next...?