Irrigation Engineering Multiple Choice Questions on “Hydraulic Jump”.
1. When the depth is small, the name for the jump?
a) Undular Jump
b) Direct Jump
c) Strong Jump
d) Oscillating Jump
Answer: a
Clarification: Whenever the jump is small the water shall not rise suddenly but will pass through a number of undulations.
2. When the change in depth is large, then the jump is said to be direct jump.
a) True
b) False
Answer: a
Clarification: In certain cases when the jump is high, then the difference in a jump is large and it occurs suddenly or abruptly.
3. For what limits of Froude number, the jump is said to be weak jump?
a) 1.1 to 2.4
b) 1.9 to 2.9
c) 1.5 to 2.2
d) 1.7 to 2.5
Answer: d
Clarification: According to Froude number from 1.7 to 2.5 a series of rollers develop on the surface of the jump, but at the downstream side the surface is smooth. The energy loss is low and a uniform velocity is maintained. The jump under these conditions is called a weak jump.
4. For the value of Froude number 9 the jump is said to be strong jump.
a) False
b) True
Answer: b
Clarification: When the value of Froude number is 9 or more, then the energy dissipation reaches up to 85% in the flow. The jump under this condition is called strong jump.
5. How many assumptions are made for the derivation of momentum formula?
a) 6
b) 3
c) 4
d) 5
Answer: c
Clarification: For the derivation of momentum formula four assumptions are made. Namely, the jump happens abruptly, friction is negligible, bed is horizontal, and flow is streamlined.
6. Depending upon the Froude number, into how many groups the jumps are classified?
a) 8
b) 6
c) 7
d) 4
Answer: b
Clarification: According the values of Froude number (F1) the jumps are classified into six groups. Namely, no jump for F1 = 1, for F1 = 1 to 1.7 the jump is undular jump, for F1 = 1.7 to 2.5 the jump is weak jump, for F1 = 2.5 to 4.5 the jump is oscillating jump, for F1 = 4.5 to 9 the jump is steady jump, and for F1 = 9 or above the jump is strong jump.
7. On which surface the energy dissipation is less efficient?
a) Horizontal Bed
b) Freeboard
c) Level Floor
d) Sloping Glacis
Answer: d
Clarification: On sloping glacis, there is less energy dissipation because the vertical component of velocity remains intact. And when a jump happens only the horizontal component of velocity impact the glacis and vertical component remains unaffected.
8. The length of the jump is how times the height of the jump?
a) 3
b) 5
c) 2
d) 4
Answer: b
Clarification: Generally the length of the hydraulic jump is calculated in a region where there is a heavy turbulence and it is found to be five times the height of the jump.
9. In what limits the slopes of the glacis are provided?
a) 2:1 to 5:1
b) 3:1 to 4:1
c) 5:2 to 6:2
d) 4:3 to 7:5