# Open Channel Flow MCQ – Uniform Flow – Set 1 (36 MCQs)

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#### Open Channel Flow MCQ – Uniform Flow – Set 1 (36 MCQs)

The following post contains Multiple Choice Questions (MCQ) covering "Uniform Flow" of Open Channel Flow / Hydraulics. Try answering the questions by yourself. Then you can check the model answers for those Open Channel Flow MCQ on the following link :

Open Channel Flow MCQ - Uniform Flow - Set 1 (Model Answer)

These Open Channel Flow MCQ covers the following topics / points of "Uniform Flow" :

The following Open Channel Flow MCQ is important for engineering students and professionals while getting ready for different engineering competitive exams. For any help, you can contact us through the comments and we will reply to you as soon as possible. You can also contact us through the following email author@3nn.4fe.myftpupload.com.

## Open Channel Flow MCQ - Uniform Flow - Set 1

### Question No.1

In a non-prismatic channel :

• unsteady flow is not possible
• the flow is always uniform
• uniform flow is not possible
• the flow is not possible

### Question No.2

In a uniform open channel flow :

• the total energy remains constant along the channel
• the total energy line either rises or falls along the channel depending on the state of the flow
• the specific energy decreases along the channel
• the line representing the total energy is parallel to the bed of the channel

### Question No.3

Uniform flow in an open channel exists when the flow is steady and the channel is :

• prismatic
• non-prismatic and the depth of the flow is constant along the channel
• prismatic and the depth of the flow is constant along the channel
• frictionless

### Question No.4

In uniform flow there is a balance between :

• gravity and frictional forces
• gravity and inertial forces
• inertial and frictional forces
• inertial and viscous forces

### Question No.5

Uniform flow is not possible if the :

• friction is large
• fluid is an oil
• So ≤ 0
• So > 0

### Question No.6

A rectangular channel of longitudinal slope 0.002 has a width of 0.80 m and carries an oil (relative density = 0.80) at a depth of 0.40 m in uniform flow mode. The average shear stress on the channel boundary in pascals is :

• 3.14 × 10–3
• 6.28 × 10–3
• 3.93 × 10–3
• 0.01256

### Question No.7

A triangular channel with a side slope of 1.5 horizontal: 1 vertical is laid on slope of 0.005. The shear stress in N/m2 on the boundary for a depth of flow of 1.5 m is :

• 3.12
• 10.8
• 30.6
• 548

### Question No.8

The dimensions of the Chezy coefficient C are :

• ${L^2}{T^{ - 1}}$
• $L{T^{ - 1/2}}$
• ${M^0}{L^0}{T^0}$
• ${L^{1/2}}{T^{ - 1}}$

### Question No.9

The dimensions of Manning’s n are :

• ${L^{1/6}}$
• ${L^{1/2}}{T^{ - 1}}$
• ${L^{ - 1/3}}T$
• ${L^{ - 1/3}}{T^{ - 1}}$

### Question No.10

The dimensions of the Darcy–Weisbach coefficient f are :

• ${L^{1/6}}$
• $L{T^{ - 1}}$
• ${L^{1/2}}{T^{ - 4}}$
• ${M^0}{L^0}{T^0}$

### Question No.11

A channel flow is found to have a shear Reynolds number u* εsν  = 25 , where εs = sand grain roughness, u* = shear velocity and ν = kinematic viscosity. The channel boundary can be classified as hydrodynamically :

• rough
• in transition regime
• smooth
• undular

### Question No.12

If the bed particle size d50 of a natural stream is 2.0 mm, then by Strickler formula, the Manning’s n for the channel is about :

• 0.017
• 0.023
• 0.013
• 0.044

### Question No.13

In using the Moody chart for finding f for open-channel flows, the pipe diameter D is to be replaced by :

• R
• D/2
• P
• 4R

### Question No.14

The Manning’s n for a smooth, clean, unlined, sufficiently weathered earthen channel is about :

• 0.012
• 0.20
• 0.02
• 0.002

### Question No.15

The Manning’s n is related to the equivalent sand grain roughness, εs as :

• $n \propto {\varepsilon _s}^{ - 1/6}$
• $n \propto {\varepsilon _s}^{1/6}$
• $n \propto {\varepsilon _s}^{1/3}$
• $n = \frac{{{\varepsilon _s}}}{{4R}}$

### Question No.16

The Darcy–Weisbach f is related to Manning’s n as :

• $f = \frac{{8g{n^2}}}{{{R^{1/3}}}}$
• $f = \frac{{{n^2}}}{{{R^{1/3}}}}$
• $f = \frac{{{R^{1/3}}}}{{8g{n^2}}}$
• $f = \frac{{64ng}}{{{R^{1/3}}}}$

### Question No.17

The Manning’s n for a straight concrete sewer is about :

• 0.025
• 0.014
• 0.30
• 0.14

### Question No.18

An open channel carries water with a velocity of 0.605 m/s. If the average bed shear stress is 1.0 N/m2, the Chezy coefficient C is equal to :

• 500
• 60
• 6.0
• 30

### Question No.19

The conveyance of a triangular channel with side slope of 1 horizontal: 1 vertical is expressed as K = C y8/3; where C is equal to :

• ${2^{8/3}}$
• $1/n$
• $1/2n$
• $2\sqrt 2 n$

### Question No.20

In a wide rectangular channel if the normal depth is increased by 20 per cent, the discharge would increase by :

• 20 {d8436e6188dc3d199bf8c3981ea7a790e12a890a66b7d0a0d43491ce624dcb00}
• 15.5 {d8436e6188dc3d199bf8c3981ea7a790e12a890a66b7d0a0d43491ce624dcb00}
• 35.5 {d8436e6188dc3d199bf8c3981ea7a790e12a890a66b7d0a0d43491ce624dcb00}
• 41.3 {d8436e6188dc3d199bf8c3981ea7a790e12a890a66b7d0a0d43491ce624dcb00}

### Question No.21

In a uniform flow taking place in a wide rectangular channel at a depth of 1.2 m, the velocity is found to be 1.5 m/s. If a change in the discharge causes a uniform flow at a depth of 0.88 m in this channel, the corresponding velocity of flow would be :

• 0.89 m/s
• 1.22 m/s
• 1.10 m/s
• 1.50 m/s

### Question No.22

It is expected that due to extreme cold weather the entire top surface of a canal carrying water will be covered with ice for some days. If the discharge in the canal were to remain unaltered, this would cause :

• no change in the depth
• increase in the depth of flow
• decrease in the depth of flow
• an undular surface exhibiting increase and decrease in depths

### Question No.23

By using Manning’s formula the depth of flow corresponding to the condition of maximum discharge in a circular channel of diameter D is :

• 0.94 D
• 0.99 D
• 0.86 D
• 0.82 D

### Question No.24

In a circular channel the ratio of the maximum discharge to the pipe full discharge is about :

• 1.50
• 0.94
• 1.08
• 1.00

### Question No.25

For a circular channel of diameter D, the maximum depth below which only one normal depth is assured :

• 0.5 D
• 0.62 D
• 0.82 D
• 0.94 D

### Question No.26

A trapezoidal channel had a 10 per cent increase in the roughness coefficient over years of use. This would represent, corresponding to the same stage as at the beginning, a change in discharge of :

• +10 {d8436e6188dc3d199bf8c3981ea7a790e12a890a66b7d0a0d43491ce624dcb00}
• –10 {d8436e6188dc3d199bf8c3981ea7a790e12a890a66b7d0a0d43491ce624dcb00}
• 11 {d8436e6188dc3d199bf8c3981ea7a790e12a890a66b7d0a0d43491ce624dcb00}
• +9.1 {d8436e6188dc3d199bf8c3981ea7a790e12a890a66b7d0a0d43491ce624dcb00}

### Question No.27

For a hydraulically-efficient rectangular section, B/yo is equal to :

• 1.0
• 2.0
• 0.5
• 1/3

### Question No.28

A triangular section is hydraulically-efficient when the vertex angle θ is :

• 90°
• 120°
• 60°
• 30°

### Question No.29

For a hydraulically efficient triangular channel with a depth of flow y, the hydraulic radius R is equal to :

• $2\sqrt 2 y$
• $y/2$
• $\sqrt 2 y$
• $y/2\sqrt 2$

### Question No.30

A hydraulically-efficient trapezoidal channel has m = 2.0. B/yo for this channel is :

• 1.236
• 0.838
• 0.472
• 2.236

### Question No.31

In a hydraulically most efficient trapezoidal channel section the ratio of the bed width to depth is :

• 1.155
• 0.867
• 0.707
• 0.50

### Question No.32

In a hydraulically efficient circular channel flow, the ratio of the hydraulic radius to the diameter of the pipe is :

• 1.0
• 0.5
• 2.0
• 0.25

### Question No.33

For a wide rectangular channel the value of the first hydraulic exponent N is :

• 3.0
• 4.0
• 3.33
• 5.33

### Question No.34

If the Chezy formula with C = constant is used, the value of the first hydraulic exponent N for a wide rectangular channel will be :

• 2.0
• 3.0
• 3.33
• 5.33

### Question No.35

For a trapezoidal channel of most-efficient proportions [ Q n / (B8/3 So1/2) ] = φ =

• 1/3
• 0.7435
• 0.8428
• 1.486

### Question No.36

In a given rectangular channel the maximum value of uniform-flow Froude number occurs when :

• $y = B/6$
• $R = y/2$
• $y = B/2$
• ${y_o} = {y_c}$

After you have checked the Open Channel Flow MCQ, you can check the model answers for those MCQ on the following link :

Open Channel Flow MCQ - Uniform Flow - Set 1 (Model Answer)

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