Complete OCF Marathon Quiz for ESE & GATE CE Exams

Question 1

For a best (or most economical) trapezoidal section

Question 2

The most efficient channel section is the one which

Question 3

Most economical circular section is designed for

Question 4

Calculate the hydraulic depth of a triangular channel having depth of flow 1.5 m and slope 45˚.

Question 5

For a given discharge, the critical flow depth in an open channel depends on

Question 6

What will be the hydraulic depth of a most efficient triangular channel if the depth of flow is 1.85 m

Question 7

Which of the following section will be the most efficient channel for the same area of cross section?

Question 8

A 4 m wide rectangular channel, having bed slope of 0.001 carries a discharge of

Considering Manning's roughness coefficient = 0.012 and

the category of the channel slope is

Question 9

Which of the following Froude number range indicates a weak jump?

Question 10

The total energy line is drawn by

Question 11

The relatively rapid flow of water in a horizontal rectangular channel can suddenly "jump" to a higher level (an obstruction downstream may be the cause). This is called a hydraulic jump. The situation is shown in the figure below. The higher depth at downstream is _________m.
[Assume uniform flow]

Question 12

A rectangular channel 2m wide carries a discharge 3m³/sec. It is observed that corresponding to a particular specific force, the conjugate depths are such that subcritical depth is thrice the supercritical depth. The subcritical depth (in metres, up two decimal places) is equal to____________.

Question 13

A rectangular channel 1.2 m wide has a bed slope of 0.0012 and the manning's roughness coefficient is 0.05. Uniform flow takes place in the channel at a flow depth of 0.4 m. At a section, flow depth is measured as 0.3 m with gradual varied flow. The GVF profile at the section is classified as

Question 14

A rectangular channel 3 m wide carries 7 m³/s flow at a depth of 0.40 m. What is the height of a flat topped hump required to be placed at a section to cause critical flow? (The energy loss due to obstruction by the hump can be taken as 0.1 times the upstream velocity head.)

Question 15

A 1 m wide rectangular channel has a bed slope of 0.0016 and the Manning’s roughness
coefficient is 0.04. Uniform flow takes place in the channel at a flow depth of 0.5 m. At a
particular section, gradually varied flow (GVF) is observed and the flow depth is measured as0.6 m. The GVF profile at that section is classified as

Question 16

The measured loss of head in a 50 mm diameter pipe conveying water at 0.6 m/s is 800 mm of water per 100 m length. The loss of head (in mm) of water per 400 m length when air flows through a 200 mm diameter pipe at the corresponding speed is
[Assume that the pipes have geometrically similar roughness and assume the densities of air and water as 1.23 and 1000 kg/m³ and the absolute viscosities of air and water are 1.8 x 10^-5 and 0.12 Pa.s respectively]

Question 17

An overflow spillway has its crest at an elevation 140.00 m and a horizontal apron at an elevation of 105.00 m on the downstream side. The prejump depth required to form a hydraulic jump when the elevation of the energy line just upstream of the spillway crest is 143.00 m is _________m.
[Assume C_d = 0.735 for the spillway and neglect energy loss due to flow over the spillway]

Question 18

The discharge was measured in a small stream. It was found that the depth of flow increased at a rate of 0.20 m/hr. If the discharge at that section was 30 m³/s and the surface width of the stream was 18 m, then the discharge at a section 1200 m upstream was ________m³/s.

Question 19

A triangular gate with a base width of 2 m and a height of 1.5 m lies in a vertical plane. The top vertex of the gate is 1.5 m below the surface of a tank which contains oil of specific gravity 0.8. Considering the density of water and acceleration due to gravity to be 1000 kg/m³ and 9.81 m/s², respectively, the hydrostatic force (in kN) exerted by the oil on the gate is __________.

Question 20

An efficient,rectangular channel with bottom width of 4.0m and a bottom slope of 0.0008 has a discharge of 1.5m³/s.In a gradually varied flow in this channel the depth at a certain location is found to be 0.30m.Assuming n=0.016,determine the type of GVF profile.

Question 21

The flow rate in a wide rectangular open channel is 2.0m²/s per meter width. The channel bed slope is 0.002. The Manning's roughness coefficient is 0.012. The slope of the channel is classified as

Question 22

A hydraulically efficient trapezoidal channel section has a uniform flow depth of 2m. The bed width (expressed in m) of the channel is __________ .

Question 23

In a wide rectangular channel if the normal depth of flow is increased by 15%, determine the corresponding percentage increase in discharge (Up to 2 decimal places). Use Manning’s equation.

Question 24

A rectangular channel is 5m wide and carries a discharge of 12 m³/sec at a depth of 3m. At a certain section of the channel it is proposed to reduce the width to 2 m and alter the bed elevation by ΔZ to obtain critical flow at the contracted section without altering the upstream depth.

The maximum value of ΔZ is __________m [rounded to two decimal places]

Question 25

Before passage of a surge, the depth and velocity of flow at a section are 1.8 m and 3.6 m/s. After the surge passage, they are 0.6 m and 8 m/s respectively. The speed of the surge is?