fundamentals of engineering supplied-reference handbook - Ventech!

Open-Channel Flow
Specific Energy
2
V αQ
E = α + y = + y , where
2
2g
2gA
2
HYDRAULIC-ELEMENTS GRAPH FOR CIRCULAR SEWERS
E = specific energy,
Q = discharge,
V = velocity,
y = depth of flow,
A = cross-sectional area of flow, and
α = kinetic energy correction factor, usually 1.0.
Critical Depth = that depth in a channel at minimum
specific energy
2
Q
g
3
A
=
T
where Q and A are as defined above,
g = acceleration due to gravity, and
T = width of the water surface.
136
For rectangular channels
y c
⎛ 2
q ⎞
= ⎜ ⎟
⎜ ⎟
⎝ g ⎠
1 3
yc = critical depth,
, where
q = unit discharge = Q/B,
B = channel width, and
g = acceleration due to gravity.
CIVIL ENGINEERING (continued)
Froude Number = ratio of inertial forces to gravity forces
V
F = , where
gy
V = velocity, and
yh = hydraulic depth = A/T
h