The flow in a pipe is turbulent when Reynold number is
Less than 2000
Between 2000 and 2800
More than 2800
None of these
Correct Answer :
C. More than 2800
Related Questions
The Bernoulli's equation is based on the assumption that
There is no loss of energy of the liquid flowing
The velocity of flow is uniform across any cross-section of the pipe
No force except gravity acts on the fluid
All of the above
In a short cylindrical external mouthpiece, the vena contracta occurs at a distance __________ the diameter of the orifice from the outlet of orifice.
Equal to
One-fourth
One-third
One-half
The shear stress-strain graph for a Newtonian fluid is a
Straight line
Parabolic curve
Hyperbolic curve
Elliptical
For similarity, in addition to models being geometrically similar to prototype, the following in both cases should also be equal
Ratio of inertial force to force due to viscosity
Ratio of inertial force to force due to gravitation
Ratio of inertial force to force due to surface tension
All the four ratios of inertial force to force due to viscosity, gravitation, surface tension, and elasticity
The resultant of all normal pressures acts
At C.G. of body
At center of pressure
Vertically upwards
At metacentre
Alcohol is used in manometers because
It has low vapour pressure
It is clearly visible
It has low surface tension
It can provide longer column due to low density
The surface tension of mercury at normal temperature is __________ that of water.
Same as
Lower than
Higher than
None of these
An error of 1% in measuring head over the crest of the notch (H) will produce an error of __________ in discharge over a triangular notch,
1 %
1.5 %
2 %
2.5 %
Which of the following statement is wrong?
A flow whose streamline is represented by a curve is called two dimensional flow.
The total energy of a liquid particle is the sum of potential energy, kinetic energy and pressure energy.
The length of divergent portion in a Venturimeter is equal to the convergent portion.
A pitot tube is used to measure the velocity of flow at the required point in a pipe.
The hammer blow in pipes occurs when
There is excessive leakage in the pipe
The pipe bursts under high pressure of fluid
The flow of fluid through the pipe is suddenly brought to rest by closing of the valve
The flow of fluid through the pipe is gradually brought to rest by closing of the valve
In an immersed body, centre of pressure is
At the centre of gravity
Above the centre of gravity
Below be centre of gravity
Could be above or below e.g. depending on density of body and liquid
The value of coefficient of velocity for a sharp edged orifice __________ with the head of water.
Decreases
Increases
Remain same
None of these
A tank of uniform cross-sectional area (A) containing liquid upto height (H1) has an orifice of cross-sectional area (a) at its bottom. The time required to empty the tank completely will be
(2A√H₁)/(Cd × a√2g)
(2AH₁)/(Cd × a√2g)
(2AH₁3/2)/(Cd × a√2g)
(2AH₁²)/(Cd × a√2g)
Two pipe systems can be said to be equivalent, when the following quantities are same
Friction loss and flow
Length and diameter
Flow and length
Friction factor and diameter
The pressure of fluid due to hammer blow is
Directly proportional to density of fluid
Inversely proportional to density of fluid
Directly proportional to (density)1/2 of fluid
Inversely proportional to (density)1/2 of fluid
The total pressure on the top of a closed cylindrical vessel of radius (r) completely filled up with liquid of specific weight (w) and rotating at (ω) rad/s about its vertical axis, is
π w ω² r²/4g
π w ω² r³/4g
π w ω² r⁴/4g
π w ω² r²/2g
Which of the following instrument can be used for measuring speed of a submarine moving in deep sea?
Venturimeter
Orifice plate
Hot wire anemometer
Pitot tube
The stability of a dam is checked for
Tension at the base
Overturning of the wall or dam
Sliding of the wall or dam
All of these
The velocity of the liquid flowing through the divergent portion of a Venturimeter
Remains constant
Increases
Decreases
Depends upon mass of liquid
In a footstep bearing, if the radius of the shaft is doubled, then the torque required to overcome the viscous resistance will be
Double
Four times
Eight times
Sixteen times
A liquid compressed in cylinder has a volume of 0.04 m3 at 50 kg/cm² and a volume of 0.039 m3 at 150 kg/cm². The bulk modulus of elasticity of liquid is
400 kg/cm²
4000 kg/cm²
40 × 10⁵ kg/cm²
40 × 10⁶ kg/cm²
Fluid is a substance that
Cannot be subjected to shear forces
Always expands until it fills any container
Has the same shear stress at a point regardless of its motion
Cannot remain at rest under action of any shear force
The maximum discharge over a broad crested weir is
0.384 Cd × L × H1/2
0.384 Cd × L × H3/2
1.71 Cd × L × H1/2
1.71 Cd × L × H3/2
Working principle of dead weight pressure gauge tester is based on
Pascal's law
Dalton's law of partial pressure
Newton's law of viscosity
Avogadro's hypothesis
When an internal mouthpiece is running free, the discharge through the mouthpiece is: (where a = Area of mouthpiece, and H = Height of liquid above the mouthpiece)
0.5 a. √2gH
0.707 a. √2gH
0.855 a. √2gH
a. √2gH
The theoretical velocity of jet at vena contracta is (where H = Head of water at vena contracta)
2gH
H × √(2g)
2g × √H
√(2gh)
When a tube of smaller diameter is dipped in water, the water rises in the tube with an upward __________ surface.
Concave
Convex
Plane
None of these
In a depressed nappe
The pressure below the nappe is atmospheric
The pressure below the nappe is negative
The pressure above the nappe is atmospheric
The pressure above the nappe is negative
The unit of kinematic viscosity in S. I. units is
N-m/s
N-s/m2
m2/s
N-m
The hydraulic mean depth or the hydraulic radius is the ratio of
Area of flow and wetted perimeter
Wetted perimeter and diameter of pipe
Velocity of flow and area of flow
None of these