A = Flow cross-sectional area [L2].
b = Channel bottom width [L].
Fr = Froude number.
Flows with F<1 are low velocity flows called subcritical.
Flows with F>1 are high velocity flows called supercritical.
Flows with F=1 are called critical.
Subcritical flows are controlled by downstream controls.
Supercritical flows are affected by upstream controls.
Fr = V/(g*ym)0.5 ,
ym = A/T
g = Acceleration due to gravity (taken as 9.8 m/s2).
H = Specific Energy [L].
K = Gauckler-Manning-Strickler coefficient [L1/3/T].
Is function of the channel material.
P = Wetted perimeter [L].
Equals the contact length between the water and the
channel bottom and sides
Q = Discharge or flow rate [L3/T].
R = Hydraulic radius of the flow cross-section [L].
(R = A/P)
S = Slope of channel bottom [L/L].
Equals vertical distance divided by horizontal distance.
T = Top width of the flowing water [L].
V = Average velocity of the water [L/T].
y = Water depth
z1, z2 = Side slopes of each bank of the channel [L/L].
computed as horizontal divided by vertical distances.
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