# Open Channel Flow MCQs with Answers

### Fluid Mechanics & Hydraulics (3140611)

#### MODULE 6: OPEN CHANNEL FLOW

1. A structure whose width is __________ the width of the channel, is called a flumed structure.
A. less than
B. more than

2. In open channels, the specific energy is the
A. total energy per unit discharge
B. total energy measured with respect to the datum passing through the bottom of the channel
C. total energy measured above the horizontal datum
D. kinetic energy plotted above the free surface of water

3. Whenever a plate is held immersed at some angle with the direction of flow of the liquid, it is subjected to some pressure. The component of this pressure, at right angles to the direction of flow of the liquid is known as lift.
A. True
B. False

4. The depth of water in a channel corresponding to the minimum specific energy is known as critical depth.
A. Agree
B. Disagree

5. The depth of water in a channel corresponding to the minimum specific energy is known as critical depth.
A. Agree

B. Disagree

6. If the depth of water in an open channel is greater than the critical depth, the flow is called
A. critical flow
B. turbulent flow
C. tranquil flow
D. torrential flow

7. The flow in a pipe or channel is said to be non-uniform when
A. the liquid particles at all sections have the same velocities
B. the liquid particles at different sections have different velocities
C. the quantity of liquid flowing per second is constant
D. each liquid particle has a definite path

8. The flow characteristics of a channel does not change with time at any point. What type of flow is it?
b) Uniform flow
c) Laminar flow
d) Turbulent flow

9. The Reynolds number for a flow in a channel is 1000. What type of flow is it?
a) Laminar
b) Turbulent
c) Transition

10. Calculate the aspect ratio having channel width of 6m and depth of 8m.
a) 0.75m
b) 1.33m
c) 1.50m
d) 1.68m
Explanation: Aspect ratio = Depth / width = 8/6 = 1.33m.

11. Calculate the mean hydraulic depth of a channel having top width of 7m and cross sectional area of
35m2.
a) 4m
b) 5m
c) 6m
d) 7m
Explanation: Hydraulic depth (D) = A/T = 35/7 = 5m.

12. The discharge in an open channel corresponding to critical depth is
(A) Zero
(B) Minimum
(C) Maximum
(D) None of these