Civil Engineering PE Hydraulics and Open-Channel Flow 2

Question 1

A rectangular channel 4 m wide carries water at a depth of 1.2 m with a velocity of 2.5 m/s. What is the Froude number?

Accepted Answer

0.73

Answer

0.63

Answer

0.83

Answer

0.93

Question 2

The hydraulic radius of a trapezoidal channel with bottom width 3 m, side slopes 1.5H:1V, and depth 1.5 m is most nearly:

Accepted Answer

0.92 m

Answer

0.82 m

Answer

1.02 m

Answer

1.12 m

Question 3

Which condition defines critical flow in an open channel?

Accepted Answer

The specific energy is at its minimum for a given discharge

Answer

The energy gradient equals the channel slope

Answer

The hydraulic radius equals the hydraulic depth

Answer

The velocity equals the wave speed of a long wave in still water

Question 4

A 600 mm diameter circular pipe flowing half-full has a hydraulic radius of:

Accepted Answer

150 mm

Answer

100 mm

Answer

200 mm

Answer

300 mm

Question 5

A hydraulic jump occurs in a rectangular channel with upstream depth y₁ = 0.4 m and upstream velocity V₁ = 6 m/s. The sequent depth y₂ is most nearly:

Accepted Answer

2.0 m

Answer

1.6 m

Answer

1.8 m

Answer

2.2 m

Question 6

Manning's equation for open channel flow requires which parameter to account for channel roughness?

Accepted Answer

Manning's roughness coefficient n

Answer

Darcy friction factor f

Answer

Chezy's coefficient C

Answer

Reynolds number Re

Question 7

The critical depth in a rectangular channel 5 m wide carrying a discharge of 20 m³/s is most nearly:

Accepted Answer

1.37 m

Answer

0.94 m

Answer

1.74 m

Answer

2.17 m