Civil Engineering PE Hydraulics and Open-Channel Flow 5

Question 1

The Chezy coefficient C is related to Manning's n by which expression (SI units)?

Accepted Answer

C = R^(1/6) / n

Answer

C = n·R^(1/6)

Answer

C = n / R^(1/6)

Answer

C = √R / n

Question 2

Flow in a steep channel (S₀ > Sc) with depth greater than critical depth carries which GVF profile classification?

Accepted Answer

S1

Answer

S2

Answer

S3

Answer

M1

Question 3

A rectangular channel 3 m wide carries Q = 15 m³/s at normal depth with n = 0.014 and S₀ = 0.001. Normal depth is most nearly:

Accepted Answer

1.75 m

Answer

1.45 m

Answer

2.05 m

Answer

2.35 m

Question 4

For a sluice gate in a wide rectangular channel with upstream depth y₁ = 2.0 m, gate opening a = 0.3 m, and Cc = 0.62, discharge per unit width assuming negligible velocity of approach is most nearly:

Accepted Answer

1.17 m²/s

Answer

0.74 m²/s

Answer

1.47 m²/s

Answer

1.85 m²/s

Question 5

The primary purpose of a stilling basin downstream of a spillway is to:

Accepted Answer

Dissipate kinetic energy via a controlled hydraulic jump to prevent scour

Answer

Increase tailwater depth to raise reservoir levels

Answer

Create supercritical conditions for accurate flow measurement

Answer

Reduce sediment transport rates through sedimentation

Question 6

The standard step method for GVF computation differs from the direct step method primarily because the standard step:

Accepted Answer

Specifies distance increments and iterates to find the corresponding depth

Answer

Only applies to prismatic channels while the direct step applies to non-prismatic channels

Answer

Specifies depth increments and directly solves for distance

Answer

Uses the momentum equation while the direct step uses the energy equation

Question 7

A circular conduit flowing at approximately 0.94D depth (not full) carries what fraction of its full-flow discharge?

Accepted Answer

About 108% of full-flow discharge

Answer

About 90% of full-flow discharge

Answer

About 100% of full-flow discharge

Answer

About 115% of full-flow discharge