# GATE Questions & Answers of Critical flow

## What is the Weightage of Critical flow in GATE Exam?

Total 20 Questions have been asked from Critical flow topic of Fluid Mechanics subject in previous GATE papers. Average marks 1.50.

For subcritical flow in an open channel, the control section for gradually varied flow profiles is

The normal depth in a wide rectangular channel is increased by 10%. The percentage increase in the discharge in the channel is:

A trapezoidal channel is 10.0 m wide at the base and has a side slope of 4 horizontal to 3 vertical. The bed slope is 0.002. The channel is lined with smooth concrete (Manning’s n = 0.012). The hydraulic radius (in m) for a depth of flow of 3.0 m is

A rectangular open channel of width 5.0 m is carrying a discharge of 100 m3/s. The Froude number of the flow is 0.8. The depth of flow (in m) in the channel is

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

The flow in a horizontal, frictionless rectangular open channel is supercritical. A smooth hump is built on the channel floor. As the height of hump is increased, choked condition is attained. With further increase in the height of the hump, the water surface will

A spillway discharges flood at a rate of 9 m3/s per metre width. If the depth of flow on the horizontal apron at the toe of the spillway is 46 cm, the tail water depth needed to form a hydraulic jump is approximately given by which of the following?

A mild-sloped channel is followed by a steep-sloped channel. The profiles of gradually varied flow in the channel are

The flow in a rectangular channel is subcritical.if the width of the channel is reduced at a certain section, the water surface under no-choke condition will

For a rectangular channel section, Group I lists geometrical elements and Group II gives proportions for hydraulically efficient section.

 Group-I Group-II P. Top width 1. $\frac{{y}_{e}}{2}$ Q.Perimeter 2. ye R.Hydraulic Radius 3. 2ye S.Hydraulic Depth 4.4ye

ye is the follow depth corresponding to hydraulically efficient section. The correct match of Group I with Group II is

The Froude number of flown in a rectangular channel is 0.8. If the depth of flow is 1.5 m, the critical depth is

Direct step method of computation for gradually varied flow is

A rectangular open channel of width 4.5m is carrying a discharge of 100 m3/sec. The critical depth of the channel is

A person standing on the bank of a canal drops a stone on the water surface. He notices that the disturbance on the water surface in not traveling up-stream. This is because the flow in the canal is

A rectangular channel 6.0 m wide carries a discharge of 16.0m3/s under uniform condition with normal depth of 1.60 m. Manning’s n is 0.015.

The longitudinal slope of the channel is

There is a free overfall at the end of a long open channel. For a given flow rate, the critical depth is less than the normal depth. What gradually varied flow profile will occur in the channel for this flow rate?

A triangular open channel has a vertex angle to 90° and carries flow at a critical depth of 0.30 m. The discharge in the channel is

The flow rate in a wide rectangular open channel is 2.0 m3/s per metre width. The channel bed slope is 0.002. The Manning’s roughness coefficient is 0.012. The slope of the channel is classified as

A rectangular open channel needs to be designed to carry a flow of 2.0 m3/s under uniform flow conditions. The Manning’s roughness coefficient is 0.018. The channel should be such that the flow depth is equal to half the width, and the Froude number is equal to 0.5.

The bed slope of the channel to be provided is