|
|
Next
consider a rectangular channel as shown in the figure below with width, w,
and liquid depth, y.
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The
table below summarizes the flow characteristics for Fr <1 (subcritical),
Fr =1 (critical)
and
Fr > 1 (supercritical) for a rectangular channel. Define
q = Q/w where Q is the
flow
rate.
|
Characteristic |
Subcritical |
Critical |
Supercritical
|
|
Depth
of Flow
|
y > yc |
y
= yc = (q2/g)1/3 |
y
< yc |
|
Velocity
of Flow
|
V < Vc |
V = Vc
= √gy |
V > Vc |
|
Slope
for
Uniform
Flow
|
Mild Slope
So < Sc |
Critical Slope
So = Sc |
Steep Slope
So > Sc |
|
Froude
Number
|
Fr < 1.0 |
Fr = 1.0 |
Fr
> 1.0 |
|
Disturbance
|
Will
propagate upstream |
Will
hold fast |
Will
form standing wave |
|
Other
Feature
|
V2/2g < ½ y |
V2/2g = ½ y |
V2/2g
> ½ y |
Click
here to continue discussion.
|