1. The laminar/viscous flow is characterized by Reynolds number which is
Correct : A. less than the critical value
2. The laminar flow is characterized by
Correct : C. Fluid particles moving in layers parallel to the boundary surface
3. In case of laminar flow, the loss of pressure head is proportional to
Correct : A. Velocity
4. The pressure gradient in the direction of flow is equal to the shear gradient in the direction
Correct : B. Normal to the direction of flow
5. …... studied the laminar flow through a circular tube experimentally
Correct : C. Hagen and Poiseuille
6. …... is the most commonly used equation for the velocity distribution for laminar flow through pipes.
Correct : B. u = umax [1- (r/R)2]
7. In laminar flow the pressure drop per unit length of pipe (∆p/L) is given as
Correct : A. 32𝜇͞u/D2
8. The K.E. correction factor a for a circular pipe is equal to
Correct : A. 2
9. The momentum correction factor b for a circular pipe is to equal to
Correct : C. 4/3
10. For viscous flow the co-efficient of friction is given by
Correct : B. f = 16/Re
11. In case of viscous flow through circular pipes
Correct : B. u = (3/2) umax
12. The maximum velocity in a circular pipe when flow is laminar occurs at
Correct : C. The centre of the pipe
13. The flow is said to be turbulent when Reynolds number is
Correct : C. Greater than 4000
14. The shear in turbulent flow is mainly due to
Correct : C. Momentum transfer
15. Which of the following statements is correct? Wall turbulence occurs
Correct : A. In immediate vicinity of solid surfaces and in the boundary layer flows where the fluid has a negligible mean acceleration
16. The flow in town water supply pipes is generally
Correct : B. Turbulent
17. The most essential feature of a turbulent flow is
Correct : D. Velocity and pressure at a point exhibit irregular fluctuations of high frequency.
18. In turbulent flow the velocity distribution is a function of the distance y measured from the boundary surface and shear friction velocity uf, and follows a
Correct : D. Logarithmic law.
19. A turbulent flow is considered steady when
Correct : C. Temporal mean velocity at a point remains constant with time
20. The Darcy-Weisbach friction factor f which is a direct measure of resistance to flow in pipes depends on which of the following?
Correct : D. Roughness height, diameter, velocity and kinematic viscosity.
21. Commercial cast-iron and steel pipes carrying fluids under pressure are regarded as hydraulically smooth when
Correct : C. The roughness elements are all completely covered by the laminar sublayer
22. Intensity of turbulence is
Correct : B. The violence of turbulent fluctuations and is measured by the root mean square value of velocity fluctuations
23. Which of the following factors determine the friction factor for turbulent flow in a rough pipe?
Correct : C. Reynolds number and relative roughness
24. In case of turbulent flow of a fluid through a circular tube (as compared to the case of laminar flow at the same flow rate) the maximum velocity is ....., shear stress at the wall is ....., and the pressure drop across a given length is ....., the correct words for the blanks are, respectively
Correct : B. lower, higher, higher
25. In a laminar flow, Reynold’s number is
Correct : A. Less than 2000
26. In a turbulent flow, Reynold’s number is
Correct : B. More than 4000
27. In case of a laminar flow, the loss of pressure head is
Correct : B. Proportional to velocity
28. In case of a turbulent flow, the loss of head is approximately proportional to
Correct : D. (Velocity) ^2
29. Darcy-Weisbach equation is used to find loss of head due to :
Correct : C. Friction
30. Chezy’s formula is given as
Correct : C. V = C√𝑚𝑖
31. Loss of head due to sudden enlargement is given as
Correct : B. (𝑉1−𝑉2)22𝑔
32. 2𝑔
148. The power transmitted through the pipe is maximum when head lost due to friction in the pipe is equal to
Correct : C. (1/5) th of the total supply head
33. The energy loss in a pipeline is due to
Correct : C. Friction offered by pipe wall as well as by viscous function
34. In a pipe flow the minor losses are those
Correct : D. Which are caused on account of total disturbance produced by such fittings as valves, bends, etc.
35. In flow through pipe bends the pressures on inner and out radii
Correct : D. Do not vary and are the same as at the center of the pipe.
36. The condition for maximum transmission of power through a pipeline is that one-third of the available
head must be consumed in friction. The corresponding efficiency of the pipeline is
Correct : B. 66·67%
37. For achieving continuous flow through a system, no position of the pipe should be higher than
Correct : C. 7·6 m
38. For turbulent flow in smooth pipes, the entrance length is taken as
Correct : B. 50
39. The entrance length or length of establishment of flow is
Correct : D. The initial length in which the flow develops fully such that the velocity profile does not change downstream.
40. Due to which of the following phenomena water hammer is caused?
Correct : D. Sudden closure (partial or complete) of a valve in pipe flow.
41. Under which of the following conditions the closure of valve is considered rapid? (where L = length of pipe, C = velocity of pressure wave produced due to water hammer.)
Correct : C. The duration of valve closure is less than 2L/C
42. The force exerted by a jet of water on a moving vertical plate, in the direction of motion of plate is given by
Correct : C. ρa (V – u)2
43. When a steady jet impinges on a fixed inclined surface
Correct : A. The flow is divided into parts proportional to the angle of inclination of the surface
44. For maximum efficiency of a series of curved vanes, the speed is
Correct : C. 1/2 of the jet speed
45. The efficiency of jet propulsion with inlet orifices at right angles to the direction of motion of ship is
given by
Correct : B. 2V/ (V + u) 2
46. For an impulse turbine which of the following statements is correct :
Correct : D. It operates with initial complete conversion of pressure head to velocity head.
47. Which of the following statements is correct in case of a Pelton wheel :
Correct : D. It operates by converting the available energy fully into kinetic energy before entering the rotor.
48. The effective (or net) head at the turbine is
Correct : C. The difference between the gross head minus head loss in penstock and the velocity head at the turbine exit
49. The difference between the power obtained from the turbine shaft and power supplied by water at its entry to the turbine is equal to
Correct : A. Sum of hydraulic and mechanical losses
50. Which of the following statements is a definition of the hydraulic efficiency of a turbine?
Correct : C. The ratio of power utilized by runner to that supplied by the water at entry to the turbine.
51. The power which appears in the expression for the specific speed is the:
Correct : A. Shaft power
52. Which of the following statements is correct: Runaway speed of a hydraulic turbine is the speed
Correct : B. At which the turbine runner can be allowed to run freely without load and with wicket gates wide open
53. Which of the following statements is correct for a reaction turbine?
Correct : D. There is only partial conversion of available head to velocity head before entry to rotor.
54. In a reaction turbine the function of a draft tube is to
Correct : C. Reconvert the kinetic energy to flow energy
55. Which of the following statements with respect to a reaction water turbine is incorrect:
Correct : B. The water leaves the turbine at atmospheric pressure
56. Which of the following turbines is suitable for specific speed ranging from 300 to 1000 and heads below 30 m:
Correct : B. Kaplan
57. Specific speed of a turbo-machine
Correct : A. Relates the shape rather than the size of the machine
58. In an outward radial flow turbine energy conversion process is
Correct : D. None of the above.
59. Which of the following turbines is least efficient under part load conditions:
Correct : A. Propeller
60. A surge tank is used to
Correct : C. Relieve the pipeline of excessive pressure transients
61. Which of the following turbines is most efficient at partload operation?
Correct : A. Kaplan
62. With respect to a Kaplan turbine which of the following statements is incorrect?
Correct : B. It is designed for flow velocity of mixed flow type.
63. Specific speed of an impulse turbine (Pelton wheel) ranges from
Correct : A. 12 to 70
64. Cavitation damage in turbine runner occurs near the
Correct : B. Outlet on the convex side of blades
65. Which of the following serious problems arise from cavitation?
Correct : D. All of the above.
66. A Kaplan turbine is
Correct : B. Low head axial flow turbine
67. An impulse turbine requires
Correct : A. High head and small quantity of flow
68. ......of a turbine is defined as the ratio of power available at the turbine shaft to the power supplied by the water jet.
Correct : C. Overall efficiency
69. The ratio of power developed by the runner to the power supplied by the jet at entrance to the turbine is
known as
Correct : A. Hydraulic efficiency
70. The water which acts on the runner blades of a reaction turbine is under a pressure
Correct : C. Above atmospheric
71. The runner passages of a reaction turbine are
Correct : B. Always completely filled with water
72. The value of speed ratio (Ku) in case of a Francis turbine ranges from
Correct : C. 0.6 to 0.9
73. The value of flow ratio (Kf) in case of a Francis turbine varies from:
Correct : B. 0.15 to 0.30
74. A Kaplan turbine claims which of the following advantages over a Francis turbine?
Correct : D. All of the above.
75. Which of the following draft tubes is suited particularly for helical flow?
Correct : C. Moody’s spreading draft tube.
76. Which of the following surge tank is also called a throttled surge tank?
Correct : C. Restricted orifice surge tank.
77. Which of the following types of impeller is used for centrifugal pumps dealing with muds?
Correct : D. Open.
78. Which of the following statements is correct with reference to an impeller with backward curved vanes?
Correct : A. It has a falling head - discharge characteristic.
79. The head developed by a centrifugal pump may be expressed as
Correct : B. H = Vw2 u2 /g
80. With reference to a centrifugal pump which of the following statements is incorrect?
Correct : D. The discharge control valve is fitted in the suction pipe.
81. A centrifugal pump should be so installed above the water level in the sump such that
Correct : B. The negative pressures do not reach as low a value as the vapour pressure
82. The specific speed of a pump is defined as the speed of unit of such a size that it
Correct : B. Delivers unit discharge at unit head
83. Which of the following statements pertaining to a given centrifugal pump is correct?
Correct : C. Discharge varies directly as speed
84. The delivery valve, while starting centrifugal pump, is kept
Correct : A. Fully closed
85. Which of the following is not a dimensionless parameter?
Correct : B. Specific speed
86. With reference to manometric head which of the following statements is correct?
Correct : D. It is the difference in the piezometric heads between the points on the delivery and suction pipes as close to the pump as possible.
87. Higher specific speeds (160 to 500) of centrifugal pump indicate that the pump is of
Correct : B. Axial flow type
88. What will happen if requirements of net positive suction head (NPSH) for a given pump are not satisfied?
Correct : A. The pump will get cavitated.
89. In centrifugal pumps, cavitation is reduced by
Correct : D. Reducing the suction head.
90. Which of the following statements pertaining to a centrifugal pump is incorrect?
Correct : A. The suction lift of a pump can be upto 10·3 m or even more.
91. Regarding cavitation which of the following statements in incorrect?
Correct : B. Thoma’s cavitation parameter has different expressions for turbines and pumps.
92. A centrifugal pump is taking much of power, the probable reason may be
Correct : A. Liquid being pumped is heavy
93. In rotodynamic pumps, the increase in energy level is due to
Correct : D. Combination of a, b and c.
94. In a pump there is
Correct : A. Accelerating flow
95. In a centrifugal pump the regulating valve is provided on
Correct : B. Delivery pipe
96. In a centrifugal pump the sum of suction head and delivery head is known as
Correct : C. Static head
97. Regarding manometric head (Hmano) which of the following relations is correct?
Correct : D. All of the above.
98. The ratio of power outlet of the pump to the power input to the pump is known as
Correct : B. Overall efficiency
99. The flow ratio in case of a centrifugal pump varies from
Correct : A. 0.1 to 0.25
100. ..... is a device which increases the intensity of pressure of a given liquid with the help of low pressure liquid of large quantity.