A: Area
C: Discharge coefficient
d: density ( water density = 1000kg/m³ )
D: Diameter
g: Gravity 9.8 m/s²
K: Flow coefficient (Kv)(Cv)
Q: Flow rate
SG: Specific gravity (1 for water)
v: Flow velocity
Δh: Head Drop (high of fluid)
ΔP: Pressure Drop

v	=	C	· SQRT ( 2 · g ·	Δh	)
cm/min cm/s ft/h ft/min ft/s fph fps in/s ips km/h km/min km/s m/h m/min m/s mi/s mi/min mph mps nmi/h yd/h yd/min yd/s				cm ft in km m mi mm nmi yd