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4

The velocity at which the flow changes from laminar flow to turbulent flow is called

A. Critical velocity

B. Velocity of approach

C. Sub-sonic velocity

D. Super-sonic velocity

Correct Answer :

A. Critical velocity


Related Questions

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4

The conditions for the stable equilibrium of a floating body are

A. The metacentre should lie above the center of gravity

B. The center of buoyancy and the center of gravity must lie on the same vertical line

C. A righting couple should be formed

D. All the above are correct

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4

Coefficient of resistance is the ratio of

A. Actual velocity of jet at vena-contracta to the theoretical velocity

B. Area of jet at vena-contracta to the area of orifice

C. Loss of head in the orifice to the head of water available at the exit of the orifice

D. Actual discharge through an orifice to the theoretical discharge

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4

A structure used to dam up a stream or river over which the water flows is called

A. Orifice

B. Notch

C. Weir

D. Dam

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4

At the center line of a pipe flowing under pressure where the velocity gradient is zero, the shear stress will be

A. Minimum

B. Maximum

C. Zero

D. Could be any value

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4

The length of a liquid stream while flowing over a weir __________ at the ends of the sill.

A. Expands

B. Does not change

C. Contracts

D. None of these

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4

The mass of 2.5 m3 of a certain liquid is 2 tonnes. Its mass density is

A. 200 kg/m3

B. 400 kg/m3

C. 600 kg/m3

D. 800 kg/m3

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4

In a free nappe,

A. The pressure below the nappe is atmospheric

B. The pressure below the nappe is negative

C. The pressure above the nappe is atmospheric

D. The pressure above the nappe is negative

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4

In order to increase sensitivity of U-tube manometer, one leg is usually inclined by angle θ. Sensitivity of inclined tube to sensitivity of Utube is equal to

A. Sinθ

B. 1/Sinθ

C. Cosθ

D. 1/Cosθ

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4

Falling drops of water become spheres due to the property of

A. Surface tension of water

B. Compressibility of water

C. Capillarity of water

D. Viscosity of water

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4

Steady flow occurs when

A. The direction and magnitude of the velocity at all points are identical

B. The velocity of successive fluid particles, at any point, is the same at successive periods of time

C. The magnitude and direction of the velocity do not change from point to point in the fluid

D. The fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane

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4

The specific gravity of an oil whose specific weight is 7.85 kN/m3, is

A. 0.8

B. 1

C. 1.2

D. 1.6

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4

A model of torpedo is tested in a towing tank at a velocity of 25 m/sec. The prototype is expected to attain a velocity of 5 m/sec. What model scale has been used?

A. 1 : 5

B. 1 : 2.5

C. 1 : 25

D. 1 : √5

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4

In a broad-crested weir, the discharge is maximum if the head of water on the downstream side of weir is __________ the head of water on the upstream side of weir.

A. Equal to

B. One-third

C. Two-third

D. Three-fourth

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4

The Francis formula for the discharge over Cipoletti weir is

A. 1.84 LH1/2

B. 1.84 LH

C. 1.84 LH3/2

D. 1.84 LH5/2

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4

The viscosity of water at 20°C is

A. One stoke

B. One centistoke

C. One poise

D. One centipoise

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4

Uniform flow occurs when

A. The flow is steady

B. The flow is streamline

C. Size and shape of the cross section in a particular length remain constant

D. Size and cross section change uniformly along length

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4

A weir is said to be broad crested weir, if the width of the crest of the weir is ________ half the height of water above the weir crest.

A. Equal to

B. Less than

C. More than

D. None of these

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4

The atmospheric pressure at sea level is

A. 103 kN/m2

B. 10.3 m of water

C. 760 mm of mercury

D. All of these

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4

The dynamic viscosity of the liquid __________ with rise in temperature.

A. Remain unaffected

B. Increases

C. Decreases

D. None of these

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4

The discharge over the trapezoidal notch is equal to the discharge over the rectangular notch __________ the discharge over the triangular notch.

A. Plus

B. Minus

C. Divide

D. None of these

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4

A flow through a long pipe at constant rate is called

A. Steady uniform flow

B. Steady non-uniform flow

C. Unsteady uniform flow

D. Unsteady non-uniform flow

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4

The coefficient of viscosity may be determined by

A. Capillary tube method

B. Orifice type viscometer

C. Rotating cylinder method

D. All of these

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4

If the coefficient of discharge is 0.6, then the discharge over a right angled notch is

A. 0.417 H5/2

B. 1.417 H5/2

C. 4.171 H5/2

D. 7.141 H5/2

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4

Fluid is a substance which offers no resistance to change of

A. Pressure

B. Flow

C. Shape

D. Volume

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4

Center of pressure compared to e.g. is

A. Above it

B. Below it

C. At same point

D. Above or below depending on area of body

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4

A flow in which the quantity of liquid flowing per second is not constant, is called

A. Streamline flow

B. Turbulent flow

C. Steady flow

D. Unsteady flow

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4

When a cylindrical vessel, containing some liquid, is rotated about its vertical axis, the liquid surface is depressed down at the axis of its rotation and rises up near the walls of the vessel on all sides. This type of flow is known as

A. Steady flow

B. Turbulent flow

C. Vortex flow

D. Uniform flow

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4

The value of coefficient of velocity for a sharp edged orifice __________ with the head of water.

A. Decreases

B. Increases

C. Remain same

D. None of these

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4

In an external mouthpiece, the absolute pressure head at vena contracta is __________ the atmospheric pressure head by an amount equal to 0.89 times the height of the liquid, above the vena contracta.

A. Less than

B. More than

C. Equal to

D. None of these

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4

If 850 kg liquid occupies volume of one cubic meter, men 0.85 represents its

A. Specific weight

B. Specific mass

C. Specific gravity

D. Specific density