CE – 325 HYDRAULICS
(Problem Set)
1. Water flows in a channel whose bottom slope is 0.003 and whose cross section is shown in the figure. The dimensions and the
Manning coefficients for the surfaces of different subsections are also given in the figure. Determine the effective Manning coefficient
for the channel.
A. 0.03242
C. 0.03355
B. 0.03536
D. 0.03424
2. Consider water flow through two identical channels with square flow sections of 4 m x 4 m. Now the two channels are combined,
forming an 8 m wide channel. The flow rate is adjusted so that the flow depth remains constant at 4 m. Determine the percent increase
in flow rate as a result of combining the channels.
A. 30.18%
C. 32.08%
B. 31.04%
D. 33.27%
3. 2 m internal diameter circular steel storm drain (n = 0.012) is to discharge water uniformly at a rate of 12 m³/s to a distance of 1 km.
If the maximum depth is to be 1.5 m, determine the required elevation drop.
A. 5.583 m
C. 6.125 m
B. 5.872 m
D. 6.367 m
4. Water is to be transported at a rate of 10 m³/s in uniform flow in an open channel whose surfaces are asphalt lined (n = 0.016). The
bottom slope is 0.0015. Determine the diameter of the best cross section of the circular channel.
A. 0.00231
C. 0.00092
B. 0.00133
D. 0.00341
5. Water discharging into an 8-m-wide rectangular horizontal channel from a sluice gate is observed to have undergone a hydraulic
jump. The flow depth and velocity before the jump are 1.2 m and 9 m/s, respectively. Determine the dissipation ratio.
6. The length of the crest of the trapezoidal weir is 3 m. If the roughness coefficient is equal to 0.015. Determine the discharge if the
head on the weir is 1 m and the slope is 0.002.
A. 9.162 m³/s
C. 10.216 m³/s
B. 9.762 m³/s
D. 10.073 m³/s
7. Pipes from three reservoirs meet at point C which is at elevation 370 m. Pressure at the junction is 150 kPa. Determine the elevation
of reservoir 3.
8. A certain part of cast iron piping of a water distribution system involves a parallel section. Both parallel pipes have a diameter of 30
cm, and the flow is fully turbulent. One of the branches (pipe A) is 1500 m long while the other branch (pipe B) is 2500 m long. If the
flow rate through pipe A is 0.4 m³/s, determine the total flow rate. Assuming pipe A has a halfway closed gate valve (k = 2.1) while
pipe B has a fully open globe valve (k = 10), and the other minor losses are negligible. Friction factor for all pipes is equal to 0.0192.
A. 0.704 m³/s
C. 0.768 m³/s
B. 0.726 m³/s
D. 0.741 m³/s
9. Oil with ρ = 876 kg/m³ and μ = 0.24 kg/m·s is flowing through a 15 cm diameter pipe that discharges into the atmosphere with a
length of 50 m. Determine the shear velocity at the walls of the pipe if the velocity in the pipe is equal to 3.5 m/s.
A. 0.23 m/s
C. 0.19 m/s
B. 0.15 m/s
D. 0.28 m/s
10. Consider uniform water flow in a 5 m wide channel made of unfinished concrete laid on a slope of 0.0022. Now water flows over
a 15-cm-high bump. If the flow over the bump is critical, determine flow depth over the bump if n = 0.014.
A. 1.943 m
c. 2.484 m
B. 2.031 m
D. 2.724 m