VIVA Questions on Fluid Mechanics lab

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

91. For hydro-dynamically smooth boundary, the friction coefficient for turbulent flow is
a) constant
b) dependent only on Reynolds number
c) a function of Reynolds number and relative roughness
d) dependent on relative roughness only
Ans: b

92. The value of friction factor 'f' for smooth pipes for Reynolds number 106 is approximately equal to
a) 0.1
b) 0.01
c) 0.001
d) 0.0001
Ans: b

93. For laminar flow in a pipe of circular cross-section, the Darcy's friction factor f is
a) directly proportional to Reynolds number and independent of pipe wall roughness
b) directly proportional to pipe wall roughness and independent of Reynolds number
c) inversely proportional to Reynolds number and indpendent of pipe wall roughness
d) inversely proportional to Reynolds number and directly proportional to pipe wall roughness
Ans: c

94. Separation of flow occurs when
a) the pressure intensity reaches a minimum
b) the cross-section of a channel is reduced
c) the boundary layer comes to rest
d) all of the above
Ans: c

96. The ratio of average velocity to maximum velocity for steady laminar flow in circular pipes is
a) 1/2
b) 2/3
c) 3/2
d) 2
Ans: a

97. The distance from pipe boundary, at which the turbulent shear stress is one-third die wall shear stress, is
a) 1/3 R
b) 1/2 R
c) 2/3 R
d) 3/4R
where R is the radius of pipe.
Ans: a

98. The discharge of a liquid of kinematic viscosity 4 cm2/sec through a 8 cm dia-meter pipe is 3200n cm7sec. The type of flow expected is
a) laminar flow
b) transition flow
c) turbulent flow
d) not predictable from the given data
Ans: a

99. The Prartdtl mixing length is
a) zero at the pipe wall
b) maximum at the pipe wall
c) independent of shear stress
d) none of the above
Ans: a

100. The velocity distribution for laminar flow through a circular tube
a) is constant over the cross-section
b) varies linearly from zero at walls to maximum at centre
c) varies parabolically with maximum at the centre
d) none of the above
Ans: c
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Fluid Mechanics Multiple choice Questions Part8
Fluid Mechanics Multiple choice Questions Part9

Computational Fluid Dynamics MCQs Multiple Choice Questions

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

81. If x is the distance from leading edge, then the boundary layer thickness in laminar flow varies as
a) x
b) x
c) x
d) x/7
Ans: a

82. Stanton diagram is a
a) log-log plot of friction factor against Reynolds number
b) log-log plot of relative roughness against Reynolds number
c) semi-log plot of friction factor against Reynolds number
d) semi-log plot of friction factor against relative roughness
Ans: a

83. The depth 'd' below the free surface at which the point velocity is equal to the average velocity of flow for a uniform laminar flow with a free surface, will be
a) 0.423 D
b) 0.577 D
c) 0.223 D
d) 0.707 D
where D is the depth of flow.
Ans: b

84. The boundary layer thickness in turbulent flow varies as
a) x"7
b) x,/2
c) x4/5
d) x3/5
where x is the distance from leading edge.
Ans: c

85. The distance y from pipe boundary, at which the point velocity is equal to average velocity for turbulent flow, is
a) 0.223 R
b) 0.423 R
c) 0.577 R
d) 0.707 R
where R is radius of pipe.
Ans: a

86. If a sphere of diameter 1 cm falls in castor oil of kinematic viscosity 10 stokes, with a terminal velocity of 1.5 cm/sec, the coefficient of drag on the sphere is
a) less than 1
b) between 1 and 100
c) 160
d) 200
Ans: c

87. In case of an airfoil, the separation of flow occurs
a) at the extreme rear of body
b) at the extreme front of body
c) midway between rear and front of body
d) any where between rear and front of body depending upon Reynolds number
Ans: a

88.     When an ideal fluid flows past a sphere,
a) highest intensity of pressure occurs around the circumference at right angles to flow
b) lowest pressure intensity occurs at front stagnation point
c) lowest pressure intensity occurs at rear stagnation point
d) total drag is zero
Ans: d

89. With the same cross-sectional area and immersed in same turbulent flow, the largest total drag will be on
a) a circular disc of plate held normal to flow
b) a sphere
c) a cylinder
d) a streamlined body
Ans: a

90. In which of the following the friction drag is generally larger than pressure drag?
a) a circular disc or plate held normal to flow
b) a sphere
c) a cylinder
d) an airfoil
Ans: d
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Fluid Mechanics Multiple choice Questions Part9

Fluid Mechanics Online Quiz Questions and Answers pdf

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

71. Coefficient of contraction for an external cylindrical mouthpiece is
a) 1.00
b) 0.855
c) 0.7H
d) 0.611
Ans: a

72. Which of the following has highest coefficient of discharge ?
a)    sharp edged orifice
b) venturimeter
c) Borda's mouthpiece running full
d) CipoUetti weir
Ans: b

73. In a Sutro weir, the discharge is proportional to
a) H1/2
b) H3/2
c) H5/2
d) H
where H is head.
Ans: d

74. The discharge over a broad crested weir is maximum when the depth of flow is
a) H/3
b) H/2
c) 2 H/5
d) 2 H/3
where H is the available head.
Ans: d

75. The speed of a pressure wave through a pipe depends upon
a) the length of pipe
b) the viscosity of fluid
c) the bulk modulus for the fluid
d) the original head
Ans: c

76. When time of closure tc = L/v0 (where L is length of pipe and v0 is speed of pressure wave), the portion of pipe length subjected to maximum head is
a) L/4
b) L/3
c) L/2
d) L
Ans: a

77. If the elevation of hydraulic grade line at the junction of three pipes is above the elevation of reservoirs B and C and below reservoir A, then the direction of flow will be
a) from reservoir A to reservoirs B and C
b) from reservoir B to reservoirs C and A
c) from reservoir C to reservoirs A and B
d) unpredictable
Ans: c

78. Which of the following statements is correct?
a) Lower critical Reynolds number is of no practical significance in pipe flow problems.
b) Upper critical Reynolds number is significant in pipe flow problems.
c) Lower critical Reynolds number has the value 2000 in pipe flow
d) Upper critical Reynolds number is the number at which turbulent flow changes to laminar flow.
Ans: a

79. For a sphere of radius 15 cm moving with a uniform velocity of 2 m/sec through a liquid of specific gravity 0.9 and dynamic viscosity 0.8 poise, the Reynolds number will be
a) 300
b) 337.5
c) 600
d) 675
Ans: d

80. The shear stress distribution for a fluid flowing in between the parallel plates, both at rest, is
a) constant over the cross section
b) parabolic distribution across the section
c) zero at the mid plane and varies linearly with distance from mid plane
d) zero at plates and increases linearly to midpoint
Ans: c
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Fluid Mechanics Multiple choice Questions Part9

Most Recently asked fluid mechanics VIVA Objective Questions

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

61. Size of a venturimeter is specified by
a) pipe diameter
b) throat diameter
c) angle of diverging section
d) both pipe diameter as well as throat diameter
Ans: a

62. Due to each end contraction, the discharge of rectangular sharp crested weir is reduced by
a) 5%
b) 10%
c) 15%
d) 20%
Ans: a

63. The discharge through a V- notch varies as
a) H1/2
b) H3'2
c) H5/2
d) H5'4 where H is head.
Ans: c

64. Which of the following is an incorrect statement ?
a) Coefficient of contraction of a venturimeter is unity.
b) Flow nozzle is cheaper than venturimeter but has higher energy loss.
c) Discharge is independent of orientation of venturimeter whether it is horizontal, vertical or inclined.
d)   None of the above statement is correct.
Ans: d

65.   Coefficient of velocity of venturimeter
a) is independent of Reynolds number
b) decreases with higher Reynolds number
c) is equal to the coefficient of discharge of venturimeter
d) none of the above
Ans: c

66. The pressure at the summit of a syphon is
a) equal to atmospheric
b) less than atmospheric
c) more than atmospheric
d) none of the above
Ans: b

67. Ay between two stream lines represents
a) velocity
b) discharge
c) head
d) pressure
Ans: b

68. Coefficient of velocity for Borda's mouth piece running full is
a) 0.611
b) 0.707
c) 0.855
d) 1.00
Ans: b

69. Coefficient of discharge for a totally submerged orifice as compared to that for an orifice discharging free is
a) slightly less
b) slightly more
c) nearly half
d) equal
Ans: a

70. The major loss of energy in long pipes is due to
a) sudden enlargement
b) sudden contraction
c) gradual contraction or enlargement
d) friction
Ans: d
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Fluid Mechanics objective questions for gate preparation

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

51.     Equation of continuity is based on the principle of conservation of
a) mass
b) energy
c) momentum
d) none of the above
Ans: a

52. In steady flow of a fluid, the total accele ration of any fluid particle
a) can be zero
b) is never zero
c) is always zero
d) is independent of coordinates
Ans: a

53. The pitot tube is used to measure
a) velocity at stagnation point
b) stagnation pressure
c) static pressure
d) dynamic pressure
Ans: b

54. Hot wire anemometer is used to measure
a) discharge
b) velocity of gas
c) pressure intensity of gas
d) pressure intensity of liquid
Ans: b

55.   The theoretical value of coefficient of contraction of a sharp edged orifice is
a) 0.611
b) 0.85
c) 0.98
d) 1.00
Ans: a

56. Which of the following is used to measure the discharge ?
a) current meter
b) venturimeter
c) pitot tube
d) hotwire anemometer
Ans: b

60. Select the incorrect statement.
a) The pressure intensity at vena contracta is atmospheric.
b) Contraction is least at vena contracta.
c) Stream lines are parallel throughout the jet at vena contracta.
d) Coefficient of contraction is always less than one.
Ans: c
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Fluid Mechanics - Mechanical Engineering MCQs

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

41. If velocity is zero over l/3rd of a cross-section and is uniform over remaining 2/3rd of the cross-section, then the correction factor for kinetic energy is
a) 4/3
b) 3/2
c) 9/4
d) 27/8
Ans: c

42. The continuity equation
pi V,A,= p2V2A2 is  based  on  the  following  assumption regarding flow of fluid
a) steady flow
b) uniform flow
c) incompressible flow
d) frictionless flow
where pi and p2 are mass densities.
Ans: a

44.   Which of the following velocity potentials satisfies continuity equation ?
a) x2y
b) x2-y2
c) cosx
d) x2 + y2
Ans: b

46.     The motion of air mass in a tornado is a
a) free vortex motion
b) forced vortex motion
c) free vortex at centre and forced vortex outside
d) forced vortex at centre and free vortex outside
Ans: d

47.     In a forced vortex motion, the velocity of flow is
a) directly proportional to its radial distance from axis of rotation
b) inversely proportional to its radial distance from the axis of rotation
c) inversely proportional to the square of its radial distance from the axis of rotation
d) directly proportional to the square of its radial distance from the axis of rotation
Ans: a

48. Stream lines and path lines always coincide in case of
a) steady flow
b) laminar flow
c) uniform flow
d) turbulent flow
Ans: a

49. For laminar flow in circular pipes, the Darcy's friction factor f is equal to
a) 16/Re
b) 32/ Re
c) 64/ Re
d) none of the above where R,, is Reynolds number.
Ans: c

50. Surge wave in a rectangular channel is an example of
i)    steady flow
ii)   unsteady flow
iii) uniform flow
iv) non-uniform flow
The correct answer is
a) (i) and (iii)
b) (ii) and (iii)
c) (i) and (:v)
d) (ii) and (iv)
Ans: d
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Fluid Mechanics – Multiple Choice Questions and Answers

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

31. A right circular cylinder open at the top is filled with liquid and rotated about its vertical axis at such a speed that half the liquid spills out, then the pressure intensity at the centre of bottom is

a) zero

b) one-fourth  its  value when  cylinder was full

c) one-half its value when cylinder was full

d) cannot be predicted from the given data

Ans: a

32. The horizontal component of force on a curved surface is equal to the

a) product of pressure intensity at its centroid and area

b) force on a vertical projection of the curved surface

c) weight of liquid vertically above the curved surface

d) force on the horizontal projection of the curved surface

Ans: b

33. A closed tank containing water is moving in a horizontal direction along a straight line at a constant speed. The tank also contains a steel ball and a bubble of air. If the tank is decelerated horizontally, then

i)    the ball will move to the front 

ii)   the bubble will move to the front 

iii) the ball will move to the rear 

iv)  the bubble will move to the rear Find out which of the above statements are correct ?

a) (i) and (ii)

b) (i)and(iv)

c) (ii) and (iii)

d) (iii) and (iv)

Ans: b

34. The eddy viscosity for turbulent flow is

a) a function of temperature only

b) a physical property of the fluid.

c) dependent on the flow

d) independent of the flow

Ans: c

35. Flow at constant rate through a tapering pipe is

i) steady flow

ii) uniform flow

iii) unsteady flow

iv) non-uniform flow

The correct answer is

a) (i) and (ii)

b) (i)and(iv)

c) (ii) and (iii)

d) (ii) and (iv)

Ans: b

36. In a two dimensional incompressible steady flow around an airfoil, the stream lines are 2 cm apart at a great distance from the airfoil, where the velocity is 30 m/sec. The velocity near the airfoil, where the stream lines are 1.5 cm apart, is

a) 22.5 m/sec.

b) 33 m/sec.

c) 40 m/sec.

d) 90 m/sec.

Ans: c

38. When the velocity distribution is uniform over the cross-section, the correction factor for momentum is

a) 0

b) 1

c) 4/3

d) 2

Ans: b

39. Least possible value of correction factor for

i) kinetic energy is zero

ii) kinetic energy is 1

iii) momentum is zero

iv) momentum is 1

The correct statements are

a) (i) and (iii)

b) (ii) and (iii)

c) (i) and (iv)

d) (ii) and (iv)

Ans: d

40. If the velocity is zero over half of the cross-sectional area and is uniform over the remaining half, then the momentum correction factor is

a) 1

b) 4/3

c) 2

d) 4

Ans: c
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Hydraulics and Fluid Mechanics Objective Questions and Answers

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

21. Centre of buoyancy always
a) coincides with the centre of gravity
b) coincides with the centroid of the volume of fluid displaced
c) remains above the centre of gravity
d) remains below the centre of gravity
Ans: b

22. If the weight of a body immersed in a fluid exceeds the buoyant force, then the body will
a) rise until its weight equals the buoyant force
b) tend to move downward and it may finally sink
c) float
d) none of the above
Ans: b

23. Metacentric height for small values of angle of heel is the distance between the
a) centre of gravity and centre of buoy-ancy
b) centre of gravity and metacentre
c) centre of buoyancy and metacentre
d) free surface and centre of buoyancy
Ans: b

24. A floating body is said to be in a state of stable equilibrium
a) when its metacentric height is zero
b) when the metacentre is above the centre of gravity
c) when the metacentre is below the centre of gravity
d) only when its centre of gravity is below its centre of buoyancy
Ans: b

25.   The increase in metacentric height
i)    increases stability
ii)   decreases stability
iii) increases comfort for passengers
iv) decreases comfort for passengers
The correct answer is
a)    (i) and (iii)
b) (i)and(iv)
c) (ii) and (iii)
d) (ii) and (iv)
Ans: b

26. A rectangular block 2 m long, 1 m wide and 1 m deep floats in water, the depth of immersion being 0.5 m. If water weighs 10 kN/m3, then the weight of the block is
a) 5kN
b) lOkN
c) 15 kN
d) 20 kN
Ans: b

27. The point in the immersed body through which the resultant pressure of the liquid may be taken to act is known as
a) centre of gravity
b) centre of buoyancy
c) centre of pressure
d) metacentre
Ans: c

28. If a vessel containing liquid moves downward with a constant acceleration equal to 'g' then
a) the  pressure  throughout the  liquid mass is atmospheric
b) there will be vacuum in the liquid
c) the pressure in the liquid mass is greater than hydrostatic pressure
d) none of the above
Ans: a

29. When a liquid rotates at a constant angular velocity about a vertical axis as a rigid body, the pressure intensity varies
a) linearly with radial distance
b) as the square of the radial distance
c) inversely as the square of the radial distance
d) inversely as the radial distance
Ans: b

30. An open cubical tank of 2 m side is filled with water. If the tank is rotated with an acceleration such that half of the water spills out, then the acceleration is equal to
a) g/3
b) g/2
c) 2g/3
d) g
Ans: d
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101 TOP Fluid Mechanics Multiple choice Questions and Answers pdf

Latest Fluid Mechanics objective questions and answers for competitive exams & interviews. Useful for freshers, students preparing for semester exams and MTech Preparation.

Fluid Mechanics Objective type Questions and Answers List

Fluid Mechanics Multiple choice Questions and Answers

1. Pascal-second is the unit of
a) pressure
b) kinematic viscosity
c) dynamic viscosity
d) surface tension
Ans: c

2. An ideal fluid is
a) one which obeys Newton's law of viscosity
b) frictionless and incompressible
c) very viscous
d) frictionless and compressible
Ans: b

3. The unit of kinematic viscosity is
a) gm/cm-sec2
b) dyne-sec/cm2
c) gm/cm2-sec
d) cm2/sec
Ans: d

4. If the dynamic viscosity of a fluid is 0.5 poise and specific gravity is 0.5, then the kinematic viscosity of that fluid in stokes is
a) 0.25
b) 0.50
c) 1.0
d) none of the above
Ans: c

5.     The viscosity of a gas
a) decreases with increase in temperature
b) increases with increase in temperature
c) is independent of temperature
d) is independent of pressure for very high pressure intensities
Ans: b

6.       Newton's law of viscosity relates
a)    intensity of pressure and rate of angular deformation
b) shear stress and rate of angular de¬formation
c) shear stress, viscosity and tempe¬rature
d) viscosity and rate of angular defor¬mation
Ans: b

7. An open tank contains 1 m deep water with 50 cm depth of oil of specific gravity 0.8 above it. The intensity of pressure at the bottom of tank will be
a) 4 kN/m2
b) 10 kN/m2
c) 12 kN/m2
d) 14 kN/m2
Ans: d

8. The position of centre of pressure on a plane surface immersed vertically in a static mass of fluid is
a) at the centroid of the submerged area
b) always above the centroid of the area
c) always below the centroid of the area
d) none of the above
Ans: c

9.     The total pressure on a plane surface inclined at an angle 9 with the horizontal is equal to
a) PA
b) pA sin 9
c) pA cos 9
d) pA tan 9
where p is pressure intensity at centroid of area and A is area of plane surface.
Ans: a

10. A vertical rectangular plane surface is submerged in water such that its top and bottom surfaces are 1.5 m and 6.0 m res-pectively below the free surface. The position of centre of pressure below the free surface will be at a distance of
a) 3.75 m
b) 4.0 m
c) 4.2m
d) 4.5m
Ans: c
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Fluid Mechanics VIVA Questions and Answers pdf free download

Fluid Mechanics Interview Questions and Answers pdf free download for freshers civil engineering students. mcqs objective type questions and Fluid Mechanics VIVA Questions and Answers

Fluid Mechanics Interview Questions and Answers List

Fluid Mechanics Interview questions and Answers

1.          Why the Centrifugal Pump is called High Discharge pump?
Centrifugal pump is a kinetic device. The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller. The centrifugal action of the impeller accelerates the liquid to a high velocity, transferring mechanical (rotational) energy to the liquid. So it discharges the liquid in high rate. It is given in the following formula:
Centrifugal force F= (M*V2)/R.
Where,
M-Mass
V-Velocity
R-Radius

2.          How Cavitation can be eliminated by Pump?
Cavitation means bubbles are forming in the liquid.
· To avoid Cavitation, we have to increase the Pump size to One or Two Inch;
To increase the pressure of the Suction Head, or
· Decrease the Pump Speed.

3.          Why Cavitation will occur in Centrifugal Pump and not in Displacement Pump?
The formation of cavities (or bubbles) is induced by flow separation, or non-uniform flow velocities, inside a pump casing. In centrifugal pumps the eye of the pump impeller is smaller than the flow area of pipe. This decrease in flow area of pump results in increase in flow rate. So pressure drop happened between pump suction and the vanes of the impeller. Here air bubbles or cavities are formed because of liquid vapour due to increase in temperature in impeller. This air bubbles are transmitted to pump which forms cavitation.

4.          Which Pump is more Efficient Centrifugal Pump or Reciprocating Pump?
Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

5.          Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?
The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure.
Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change.
One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.

6. How Cavitation can be eliminated in a Pump?
Cavitation means bubbles are forming in the liquid.
· To avoid Cavitation, we have to increase the Pump size to One or Two Inch;
· To increase the pressure of the Suction Head, or
· Decrease the Pump Speed.

7. Which pump is more efficient Centrifugal pump or Reciprocating pump?
Centrifugal pump.
Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

8. Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?
The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure.
Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change.
One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.

9. What is a radial-flow turbine?
In a radial-flow turbine, steam flows outward from the shaft to the casing. The unit is usually a reaction unit, having both fixed and moving blades.

10. What are four types of turbine seals?
Carbon rings fitted in segments around the shaft and held together by garter or retainer springs.
Labyrinth mated with shaft serration’s or shaft seal strips.
Water seals where a shaft runner acts as a pump to create a ring of water around the shaft. Use only treated water to avoid shaft pitting.
Stuffing box using woven or soft packing rings that are compressed with a gland to prevent leakage along the shaft.

11. What are two types of clearance in a turbine?
Radial – clearance at the tips of the rotor and casing.
Axial – the fore-and-aft clearance, at the sides of the rotor and the casing.

12. What is the function of a thrust bearing?
Thrust bearings keep the rotor in its correct axial position.

13. What is a stage in a steam turbine?
In an impulse turbine, the stage is a set of moving blades behind the nozzle. In a reaction turbine, each row of blades is called a "stage." A single Curtis stage may consist of two or more rows of moving blades.

14. What is a diaphragm?
Partitions between pressure stages in a turbine’s casing are called diaphragms. They hold the vane-shaped nozzles and seals between the stages. Usually labyrinth-type seals are used. One-half of the diaphragm is fitted into the top of the casing, the other half into the bottom.

15. What are the two basic types of steam turbines?
Impulse type.
Reaction type.

16. What are topping and superposed turbines?
Topping and superposed turbines arc high-pressure, non-condensing units that can be added to an older, moderate-pressure plant. Topping turbines receive high-pressure steam from new high-pressure boilers. The exhaust steam of the new turbine has the same pressure as the old boilers and is used to supply the old turbines.

17. What is a combination thrust and radial bearing?
This unit has the ends of the Babbitt bearing extended radically over the end of the shell. Collars on the rotor face these thrust pads, and the journal is supported in the bearing between the thrust collars.

18. How Cavitation can be eliminated in a Pump?
• Increase the Pump size to One or Two Inch,
• Increase the pressure of the Suction Head,
• Decrease the Pump Speed.

19. One litre = ________cm3 .
1000 cm3 .

20. Which Pump is more Efficient Centrifugal Pump or Reciprocating Pump?
Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

21. Differentiate between the Uniform Flow and Non-Uniform Flow?
Uniform Flow:   The flow is defined as uniform flow when in the flow field the velocity and other hydrodynamic parameters do not change from point to point at any instant of time.
Non-Uniform Flow:      When the velocity and other hydrodynamic parameters changes from one point to another the flow is defined as non-uniform flow.

22. What is Coefficient of contraction?
Coefficient of contraction is the ratio of area of jet at vena contracta to the area of orifice.
The typical value may be taken as 0.64 for a sharp orifice (concentric with the flow channel). The smaller the value, the more effect the vena contracta has.

TOP 22 Fluid Mechanics Interview questions and Answers pdf

Fluid Mechanics Interview Questions and Answers pdf free download for freshers civil engineering students. mcqs objective type questions and Fluid Mechanics VIVA Questions and Answers

Fluid Mechanics Interview Questions and Answers List

Fluid Mechanics Interview questions and Answers

1.          Why the Centrifugal Pump is called High Discharge pump?
Centrifugal pump is a kinetic device. The centrifugal pump uses the centrifugal force to push out the fluid. So the liquid entering the pump receives kinetic energy from the rotating impeller. The centrifugal action of the impeller accelerates the liquid to a high velocity, transferring mechanical (rotational) energy to the liquid. So it discharges the liquid in high rate. It is given in the following formula:
Centrifugal force F= (M*V2)/R.
Where,
M-Mass
V-Velocity
R-Radius

2.          How Cavitation can be eliminated by Pump?
Cavitation means bubbles are forming in the liquid.
· To avoid Cavitation, we have to increase the Pump size to One or Two Inch;
To increase the pressure of the Suction Head, or
· Decrease the Pump Speed.

3.          Why Cavitation will occur in Centrifugal Pump and not in Displacement Pump?
The formation of cavities (or bubbles) is induced by flow separation, or non-uniform flow velocities, inside a pump casing. In centrifugal pumps the eye of the pump impeller is smaller than the flow area of pipe. This decrease in flow area of pump results in increase in flow rate. So pressure drop happened between pump suction and the vanes of the impeller. Here air bubbles or cavities are formed because of liquid vapour due to increase in temperature in impeller. This air bubbles are transmitted to pump which forms cavitation.

4.          Which Pump is more Efficient Centrifugal Pump or Reciprocating Pump?
Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

5.          Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?
The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure.
Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change.
One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.

6. How Cavitation can be eliminated in a Pump?
Cavitation means bubbles are forming in the liquid.
· To avoid Cavitation, we have to increase the Pump size to One or Two Inch;
· To increase the pressure of the Suction Head, or
· Decrease the Pump Speed.

7. Which pump is more efficient Centrifugal pump or Reciprocating pump?
Centrifugal pump.
Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

8. Why Centrifugal Pump is not called as a Positive Displacement Type of Pump?
The centrifugal has varying flow depending on pressure or head, whereas the Positive Displacement pump has more or less constant flow regardless of pressure.
Likewise viscosity is constant for positive displacement pump where centrifugal pump have up and down value because the higher viscosity liquids fill the clearances of the pump causing a higher volumetric efficiency. When there is a viscosity change in supply there is also greater loss in the system. This means change in pump flow affected by the pressure change.
One more example is, positive displacement pump has more or less constant efficiency, where centrifugal pump has varying efficiency rate.

9. What is a radial-flow turbine?
In a radial-flow turbine, steam flows outward from the shaft to the casing. The unit is usually a reaction unit, having both fixed and moving blades.

10. What are four types of turbine seals?
Carbon rings fitted in segments around the shaft and held together by garter or retainer springs.
Labyrinth mated with shaft serration’s or shaft seal strips.
Water seals where a shaft runner acts as a pump to create a ring of water around the shaft. Use only treated water to avoid shaft pitting.
Stuffing box using woven or soft packing rings that are compressed with a gland to prevent leakage along the shaft.

11. What are two types of clearance in a turbine?
Radial – clearance at the tips of the rotor and casing.
Axial – the fore-and-aft clearance, at the sides of the rotor and the casing.

12. What is the function of a thrust bearing?
Thrust bearings keep the rotor in its correct axial position.

13. What is a stage in a steam turbine?
In an impulse turbine, the stage is a set of moving blades behind the nozzle. In a reaction turbine, each row of blades is called a "stage." A single Curtis stage may consist of two or more rows of moving blades.

14. What is a diaphragm?
Partitions between pressure stages in a turbine’s casing are called diaphragms. They hold the vane-shaped nozzles and seals between the stages. Usually labyrinth-type seals are used. One-half of the diaphragm is fitted into the top of the casing, the other half into the bottom.

15. What are the two basic types of steam turbines?
Impulse type.
Reaction type.

16. What are topping and superposed turbines?
Topping and superposed turbines arc high-pressure, non-condensing units that can be added to an older, moderate-pressure plant. Topping turbines receive high-pressure steam from new high-pressure boilers. The exhaust steam of the new turbine has the same pressure as the old boilers and is used to supply the old turbines.

17. What is a combination thrust and radial bearing?
This unit has the ends of the Babbitt bearing extended radically over the end of the shell. Collars on the rotor face these thrust pads, and the journal is supported in the bearing between the thrust collars.

18. How Cavitation can be eliminated in a Pump?
• Increase the Pump size to One or Two Inch,
• Increase the pressure of the Suction Head,
• Decrease the Pump Speed.

19. One litre = ________cm3 .
1000 cm3 .

20. Which Pump is more Efficient Centrifugal Pump or Reciprocating Pump?
Centrifugal pump. Because flow rate is higher compared to reciprocating pump. Flow is smooth and it requires less space to install. Lower initial cost and lower maintenance cost.

21. Differentiate between the Uniform Flow and Non-Uniform Flow?
Uniform Flow:   The flow is defined as uniform flow when in the flow field the velocity and other hydrodynamic parameters do not change from point to point at any instant of time.
Non-Uniform Flow:      When the velocity and other hydrodynamic parameters changes from one point to another the flow is defined as non-uniform flow.

22. What is Coefficient of contraction?
Coefficient of contraction is the ratio of area of jet at vena contracta to the area of orifice.
The typical value may be taken as 0.64 for a sharp orifice (concentric with the flow channel). The smaller the value, the more effect the vena contracta has.