Marks 1
G1 and G2 are the slopes of the approach and departure grades of a vertical curve, respectively.
Given |G1| < |G2| and |G1| ≠ |G2| ≠ 0
Statement 1 : +G1 followed by +G2 results in a sag vertical curve.
Statement 2 : −G1 followed by −G2 results in a sag vertical curve.
Statement 3 : +G1 followed by −G2 results in a crest vertical curve.
Which option amongst the following is true?
A hydraulic jump takes place in a 6 in wide rectangular channel at a point where the upstream depth is 0.5 m (just before the jump). If the discharge in the channel is 30 m3/s and the energy loss in the jump is 1.6 m, then the Froude number computed at the end of the jump is _________. (round off to two decimal places)
(Consider the acceleration due to gravity as 10 m/s2.)
Water is flowing in a horizontal, frictionless, rectangular channel. A smooth hump is built on the channel floor at a section and its height is gradually increased to reach choked condition in the channel. The depth of water at this section is y2 and that at its upstream section is y1. The correct statements for the chocked and un-chocked conditions in the channel is/are
A rectangular channel with Gradually Varied Flow (GVF) has a changing bed slope. If the change is from a steeper slope to a steep slope, the resulting GVF profile is
Depth of water flowing in a 3 m wide rectangular channel is 2 m. The channel carries a discharge of 12 m3/s. Take g = 9.8 m/s2. The bed width (in m) at contraction, which just causes the critical flow, is _________ without changing the upstream water level. (round off to two decimal places)
Marks 2
A compound symmetrical open channel section as shown in the figure has a maximum of _______ critical depth(s).
Bm – Bottom width of main channel
Bf – Bottom width of flood channel
ym – Depth of main channel
y – Total depth of the channel
nm – Manning’s roughness of the main channel
nf – Manning’s roughness of the flood channel
The critical flow condition in a channel is given by _______.
[Note: 𝛼 – kinetic energy correction factor; 𝑄 – discharge; Ac – cross-sectional area of flow at critical flow condition; Tc – top width of flow at critical flow condition; 𝑔 – acceleration due to gravity]
The cross-section of a small river is sub-divided into seven segments of width 1.5 m each. The average depth, and velocity at different depths were measured during a field campaign at the middle of each segment width. The discharge computed by the velocity area method for the given data is _____ m3/s (round off to one decimal place).
| Segment | Average depth (D) (m) | Velocity (m/s) at 0.2D | Velocity (m/s) at 0.6D | Velocity (m/s) at 0.8D |
|---|---|---|---|---|
| 1 | 0.40 | -- | 0.40 | -- |
| 2 | 0.70 | 0.76 | -- | 0.70 |
| 3 | 1.20 | 1.19 | -- | 1.13 |
| 4 | 1.40 | 1.25 | -- | 1.10 |
| 5 | 1.10 | 1.13 | -- | 1.09 |
| 6 | 0.80 | 0.69 | -- | 0.65 |
| 7 | 0.45 | -- | 0.42 | -- |
A very wide rectangular channel carries a discharge (Q) of 70 m3/s per meter width. Its bed slope changes from 0.0001 to 0.0009 at a point P, as shown in the figure (not to scale). The Manning’s roughness coefficient of the channel is 0.01. What water surface profile(s) exist(s) near the point P?
