Sample Problem
Solution:
Sketch: see figure
Assumptions: uniform flow, steady, slope=2o
Required: Determine flow rate, Q (ft3/s)
Model: Apply Chezy’s and Manning’s formulas
Chezy’s Q = CARh1/2So 1/2
Manning’s Q = K/n*A Rh2/3So 1/2
Refer to Examples 12.1 and 12.2 on Pages 654 to 657
EXAMPLE 12.1
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EXAMPLE 12.1 (continued)
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EXAMPLE 12.1 (continued)
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EXAMPLE 12.1 (continued)
EXAMPLE 12.2
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EXAMPLE 12.2 (continued)
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EXAMPLE 12.2 (continued)
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EXAMPLE 12.2 (continued)
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EXAMPLE 12.2 (continued)
Open Channels- Sample Problems
Problem 12.6
Assumptions:
• Incompressible flow
• The flow is steady
• For rectangular channel, critical flow occurs at critical depth, y c
Solution-Cntd
Sample Problem
Assumptions:
• Incompressible flow
• The flow is steady
• For rectangular channel, critical flow occurs at critical depth, y
Solution Cntd
Hydraulic Jump-Sample Problem
A sluice gate used to control a section of rectangular channel 60 ft
wide has an opening 2.5 ft deep and discharges water at the rate of
2500ft3/s. If a hydraulic jump is created on the downstream side of the
sluice gate;
(i) Sketch and label the described features of this channel/sluice gate
setup.
(ii) Determine the height and type of the hydraulic jump.
(iii) The percentage head loss due to the jump created.
(iv) The power dissipated (in hp) in the jump.
(v) Comment on the significance and strategies adopted to account
for or regulate the “hydraulic jumps” during the design of the
hydropower spillways.