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**" :

- Uniform Flow Definition
- Chezy Equation
- Darcy-Weisbach Friction Factor
*f* - Manning Equation
- Velocity Distribution in Open Channel Flow
- Shear Stress Distribution in Open Channel Flow
- Manning Roughness Coefficient
*n* - Equivalent Roughness
- Strickler's Formula
- Uniform Flow Computations
- Lined Canal Sections
- Maximum Discharge through a Cross Section
- Hydraulically Efficient Channel Cross Section (Best Hydraulic Cross Section)
- Second Hydraulic Exponent
- Compound Channels
- Critical Slope
- Generalized Flow Relation
- Design Methods of Irrigation Channels

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
- S
_{o}≤ 0 - S
_{o}> 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/m^{2} 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* ε _{s}* /

*ν*= 25 , where

*ε*= sand grain roughness,

_{s}*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 d_{50}** of a natural stream is 2.0 mm, then by

**Strickler formula**, the

**Manning’s**for the channel is about :

*n*- 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**is to be

*D***replaced**by :

*R**D*/2*P*- 4
*R*

### 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,**as :

*ε*_{s}- \[n \propto {\varepsilon _s}^{ - 1/6}\]
- \[n \propto {\varepsilon _s}^{1/6}\]
- \[n \propto {\varepsilon _s}^{1/3}\]
- \[n = \frac{{{\varepsilon _s}}}{{4R}}\]

### Question No.16

The **Darcy–Weisbach f** is related to

**Manning’s**as :

*n*- \[f = \frac{{8g{n^2}}}{{{R^{1/3}}}}\]
- \[f = \frac{{{n^2}}}{{{R^{1/3}}}}\]
- \[f = \frac{{{R^{1/3}}}}{{8g{n^2}}}\]
- \[f = \frac{{64ng}}{{{R^{1/3}}}}\]

### 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/m^{2}, 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 y^{8/3}**; where

*is equal to :*

**C**- \[{2^{8/3}}\]
- \[1/n\]
- \[1/2n\]
- \[2\sqrt 2 n\]

### 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*/

*is equal to :*

**y**_{o}- 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**is equal to :

*R*- \[2\sqrt 2 y\]
- \[y/2\]
- \[\sqrt 2 y\]
- \[y/2\sqrt 2 \]

### Question No.30

A **hydraulically-efficient trapezoidal** channel has ** m = 2.0**.

**for this channel is :**

*B*/*y*_{o}- 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**for a

*N***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 / (B^{8/3} S_{o}^{1/2}) ] = 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 :

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