ACE Engineering Academy APPS APPSC C – 2012 2012 (Mo (Mode dell Exam Exam)) SUB: FLUID FLUID MECHANICS MECHANICS & MACHINERY MACHINERY Branch: Civil & Mechanical Engineering Time : 75 Minutes
1. One cubic cubic meter meter of of water water weigh weighss (a) 100 liters (b) 250 liters
Maximum Marks : 75
(c) 500 liters
(d) 1000 liters
2. Mercury Mercury does does not not stick stick to to glass glass surface surface becau because se (a) cohesive forces are greater than adhesive forces (b) adhesive forces are greater than cohesive forces (c) cohesive forces are equal to adhesive forces (d) internal friction is negligible 3. For any fluid fluid if shear shear rate rate is proportion proportional al to the shear shear stres stresss the fluid fluid is is known known as (a) Reynold fluid (b) viscous fluid (c) Rigid fluid (d) Newtonian fluid 4. Given = 0.06 poise and = 0.9 gm/cm , what is the value of kinematic viscosity in stokes? (a) 0.04 (b) 0.054 (c) 0.066 (d) 0.082 3
5. A Jet Jet of water issuing issuing from a nozzle nozzle with a velocit velocity y 20m/s hits hits a flat plate moving moving away away 2 from it at 10m/s. The The cross-sectional cross-sectional area of the jet is 100cm . What is the force on the plate? (a) 100N (b) 10 N (c) 10000 N (d) 1000 N 6. Consid Consider er the strea stream m func function tion = 2xy; what is the velocity at (3,4)? (a) 1.0 m/s (b) 8.0 m/s (c) 10.0 m/s (d) 12.0 m/s 7. A 15 cm diameter diameter pipe carries carries 70 lit/s of oil (sp.gr. (sp.gr. = 0.75). 0.75). At a section 62 cm above above the datum, the pressure is 2 cm vacuum of mercury (sp. gr. = 13.6). Assuming Assuming kinetic energy correction factor of 1.1, what is the total head in m of oil at the t he section? (a) 1.057 (b) 1.137 (c) 1.148 (d) 1.228 8. In flow over over a V-notch, V-notch, how much error in the computation of discharge discharge over the notch would arise from an error of 1% in i n the measurement of head over the notch? (a) 1% (b) 1.5 % (c) 2% (d) 2.5%
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16V 2 . What is the equivalent All minor losses in a 15cm diameter pipeline add up to 2g length of a pipeline of same diameter with Darcy’s f = 0.03 for this condition? (a) 160 m (b) 80 m (c) 20 m (d) 9 m 3
10. A buoy 2m in volume and 1 tonne in weight is fully submerged at high tide in a harbor and is held down by a chain. The specific gravity of seawater may be assumed as 1.025. What is the value of the tension in the chain? (a) 2.00 tonne (b) 1.00 tonne (c) 2.05 tonne (d) 1.05 tonne 11. Consider the following four values of pressure: 1. 15 m of water 2. 100 kPa 3. 2 m of mercury 4. 2000 millibar What is the correct sequence of these pressure magnitudes in descending order? (a) 3- 4 – 1 – 2 (b) 4 – 3 – 1 – 2 (c) 3 – 1 – 2 – 4 (d) 4 – 2 – 1 – 3 12. A triangular lamina with base 3m and height 3m is immersed in water vertically with base parallel to water surface and vertex touching the water surface. What is the value of total water pressure on one face of the lamina? (a) 90 kN (b) 67.5 kN (c) 135 kN (d) 180 kN 13. If glass tube of small diameter d is dipped in a liquid, what is the height of rise/fall of the liquid meniscus in the tube? 4d 4 cos cos d (a) (b) (c) (d) 4d 4 cos cos d Where ; is specific weight of the liquid is surface tension of the liquid in the tube.
is the relevant angle
14. Surface tension of fluids is expressed as 2 (a) N/m (b) J/ m (c) Both (a) & (b)
2
(D) N-m
15. A fluid has a kinematic viscosity of four stokes and a specific gravity of three. Then the 2 viscosity of the fluid, in N.s/m is: (a) 0.6 (b) 0.8 (c) 1.0 (d) 1.2 16. A fluid jet is discharging from a 100mm diameter orifice and the vena contracta formed as a diameter of 90mm. the coefficient of velocity is 0.95, then the coefficient of discharge for the orifice is: (a) 0.7695 (b) 0.81 (c) 0.9025 (d) 0.855 17. A piping system consisting of three pipes arranged in series, the lengths oh the pipes are 1.2Km, 0.75Km and 0.6Km and diameters are 75cm, 60cm and 45cm respectively. Transform the system to an equivalent 45cm diameter pipe: (a) 0.6713Km (b) 0.7713Km (c) 0.8713Km (d) 0.9713Km
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18. A cylindrical tank of 200cm diameter is laid with its horizontal and is filled with an oil (s=0.9) just to its top. The force on one of its end plates in kN, is: (a)110 (b) 53.3 (c) 27.7 (d) 17.6 19. The total pressure force acts through a point known as: (a) centre of gravity (b) center of buoyancy (c) centre of pressure (d) centroid of the surface 20. Working principle of “Dead – Weight Pressure Gauge Tester” is based on: (a) Newton’s law of viscosity (b) Avogadro’s hypothesis (c) Pascal’s law (d) Dalton’s law of partial pressure 21. one meter of water column is equal to : 2 2 (a) 100 kN/m (b) 10 kN/m
(c) 1 kN/m
2
(d) 0.1 kN/m
2
22. In a lock gate, the reaction between two gates is p 2p p p (a) (b) (c) (d) sin sin 2 sin sin / 2 Where p = Resultant pressure force on the lock gate, and = Inclination of the gate with the normal to the side of the lock. 23. The gauge reading in a Mercury-Water Differential Manometer is 50 cm of mercury, then the water differential head is: (a) 3.15 m (b) 6.3m (c) 0.5 m (d) 1.0 m 24. The Meta centric height of a ship is 60cm and the radius of gyration is 4 m. The time of rolling of oscillations of ship is: (a) 4.1 s (b) 5.2 s (c) 10.4 s (d) 14.1 s 25. If a cubical water tank filled with water is accelerated to half the gravity along one of its sides, the amount of water that spills out is : (a) half (b) one-fourth (c) two-third (d) three-fourth 26. Stream lines, streak lines, path lines are all identical in case of: (a) uniform flow (b) non-uniform flow (c) both (a) & (b) 27. A non – uniform, steady flow is through (a) a long tube at a decreasing rate (c) an expanding tube at constant rate
(d) Steady flow
(b) an expanding tub a increasing rate (d) an expanding tube at increasing rate
28. The value of Darcy’s coefficient of friction for laminar flow in a pipe with Reynolds number 2000 is: (a) 0.032 (b) 0.008 (c) 0.004 (d) 0.0005 29. In a forced vortex flow, velocity ‘V’ and radial distance ‘r’ are related as: 2 2 (a) V r (b) V 1 / r (c) V 1/ r (d) V r
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30. A pump delivers 50 L/s of water and consumes 10HP of power by the pump system. The head developed by the pump is: (a) 7.5 m (b) 5.0 m (c) 1.53 m (d) 15.00 m 31. A pitot tube (coefficient of velocity = 0.98) is used to measure the velocity of air of mass 3 density 1.2kg/m . If the head difference in vertical U-tube filled water is 12 mm, then the velocity of air (in m/s) will be: (a) 10.72 (b) 13.72 (c) 17.38 (d) 14.00 2
32. A jet of oil (RD = 0.8) has an area of 200cm and a velocity of 600 m/min. If it strikes a plate normally, the force exerted on the plate is (a) 1.6KN (b) 19.96 KN (c) 15.66 KN (d) 19.58 KN 33. A jet of water strikes a flat vertical plate moving in the direction of jet at one-third the velocity of the jet. Then the force exerted by the jet on the plate is given by K AV 2 (a) 3/2
V where K is equal to: (b) 2/3
(c) 9/4
(d) 4/9
34. The loss of head in turbulent flow in pipes varies: (a) as the square of the velocity of flow (b) as the diameter of pipe (c) linearly as the velocity of flow (d) inversely with the are of pipe 35. Water is flowing in a 4cm diameter pipe with a velocity of 54 m/ min. What will be the loss of head if at a certain section the pipe diameter is i ncreased to 6cm sudden? (a) 12.5 mm (b) 44.44 mm (c) 15 mm (d) 30 mm 36 Two pipe systems in series are said to be equivalent when: (a) the average diameter in both systems is same (b) the average friction factor in both systems is same (c) the total length of the pipes is same in both the systems (d) the discharge under the same head is same in both the systems 37. In a laminar flow through a circular pipe of diameter 200mm, the maximum velocity is found to be 10 m/s. The velocity at a radial distance of 5cm from the axis of the pipe will be: (a) 2.5m/s (b) 5.0m/s (c) 7.5m/s (d) 10m/s 38. Which one of the following equation represents the laminar flow of real fluids? (a) Euler’s
(b) Bernoulli’s
(c) Hagen’s
(d) Navier-Stoke’s
39. Moody’s charts are the graphical presentation between: (a) Reynold’s number and pressure head (b) Velocity and Reynold’s number (c) Friction factor and velocity of fluid (d) Friction factor and Reynold’s number 40. An Orifice fitted with some kind of extension in the form of a pipe or tube is called: (a) Free orifice (b) Submerged orifice (c) Mouthpiece (d) Elbow meter
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41. The head over 90 V – notch weir increases from 0.1 to 0.2m. The ratio the new discharge to the original discharge is: (a) 1.414 (b) 2.000 (c) 4.000 (d) 5.657 42. Cippolletti weir is a trapezoidal weir having side slopes of: (a) 1 H: 2V (b) 4H: 1V (c) 1H: 4V
(d) 1H: 3V
43. The continuity equation for one dimensional compressible fluid flow is (a) d(AV) 0 (b) d(AV) = 0 (c) d (AV) = 0 (d) d(AV) ≠ 0 44. Mach cone is possible in (a) Stationary fluids (c) Transonic flow
(b) Subsonic flow (d) Supersonic flow
45. Which of the flowing instrument can be used for measuring the speed of aero plane? (a) venturimeter (b) Hot wire anemometer (c) Rotameter (d) Pitot tube 46. Which of the following is conventional source of power generation? (a) Tidal power (b) Geo-thermal power (c) wind power
(d) Hydro-power
47. In hydropower plants (a) initial cost is high and operating cost is low (b) initial cost as well as operating cost are high (c) initial cost is low and operating cost is high (d) initial cost as well as operating cost are low 48. A pumped storage plant is a (a) high head plant (c) peak load plant
(b) run-off river plant (d) base load plant
49. An impulse turbine (a) always operates submerged (b) makes use of draft tube (c) is most suited for low head installations (d) operates by initial complete conversion to kinetic head. 50. For maximum efficiency, the best runner speed in terms of jet velocity ‘V’ is (a) V/2 (b) V (c) 2V (d) V/3 51. The usual number of buckets for a pelton wheel are (a) 10-12
(b) 12-18
52. The shaft of a Kaplan runner is generally kept (a) horizontal (b) vertical
(c) 18-22
(c) inclined
53. The discharge through a Francis turbine runner is given by (a) K D1 B1 V1 (b) K D2 B2 Vf2 (c) K D1 Vf1
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(d) more than 30
(d) anything
(d) K
D1 B1 U1
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54. A draft tube is a part of the installation of a (a) propeller turbine (b) Pelton turbine (c) turbine impulse wheel (d) all the turbines 55. The purpose of turbines governing mechanism is to have (a) synchronous speed with that of generator (b) maximum speed (c) uniform discharge irrespective of demand (d) none of the above. 56. The Run Away Speed of a turbine is (a) Maximum speed under no load but with governing (b) Maximum speed under no load and no governing (c) Maximum speed under full load (d) Speed aliened when governor is disconnected. 57. The ratio of specific speeds of a single jet Pelton Wheel to that of a multiple jet (N jets) Pelton wheel is (a) N : 1
(b) 1: N
(c) 1: N
(d)
N:1
58. The net of effective head at the turbine is (a) gross head + head loss in pen stock (b) gross head + head loss in pen stock + velocity head at turbine exit (c) gross head – head loss in pen stock (d) gross head – head loss in pen stock – velocity head at turbine exit. 59. Cavitation occurs in (a) Impulse turbine (c) both (a) and (b)
(b) Reaction turbines (d) None
60. The action of centrifugal pump is (a) Reverse of radially in ward flow reaction turbine (b) Reverse of propeller turbine (c) Reverse of mixed flow turbine (d) None 61. The purpose of priming is to (a) Drive out water from sump (b) Fill the suction pipe with water (c) Fill the delivery pipe with water (d) Drive out air or gas or vapour from suction pipe, casing and part of delivery valve. 62. If the shaft H.P of the motor of a centrifugal pump be ‘P’, the overall efficiency of the pump is (P in H.P) 2 2 (a) WQH /P (b) WQ H/75P (c) WQH/ 75 P (d) WQH/125 P 3
63. A reservoir has a head of 40 m and discharging 34 m /sec. The speed of the runner is 150 rpm. The type of turbine to be used is (a) Pelton wheel (b) Francis Turbine (c) Kaplan Turbine (d) none of these
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64. The diameter and width of a centrifugal pump at outlet are 30 cm and 5 cm. Calculate discharge if velocity of flow at outlet is 3.556 m/sec. 3 3 3 3 (a) 0.25m /sec (b) 0.35m /sec (c) 0.17m /sec (d) 0.51m /sec 3
65. A centrifugal pump has overall efficiency 75% and delivers 0.03 m /sec, manometric head 3 is 25 m, and Power developed, in kW. Assume w = 10 kN/m . (a) 10 (b) 7.5 (c) 5.625 (d) 5 66. The turbine suitable for low heads and high flow rate is (a) Pelton wheel (b) Francis turbine (c) Kaplan (d) All the above 67. The dynamic thrust exerted by a jet, on a flat plate moving with velocity ‘u’ in the direction of jet velocity ‘v’, normal to the plate will be: (a)
wa v u
(b)
g
(c) wa v u
3
(d)
wa v u
2
g wa v u
2
g
Where w = specific weight of fluid
68. The hammer blow in pipes occurs when: (a) there is excessive leakage in the pipe (b) the pipe bursts under high pressure of fluid (c) the flow of fluid through the pipe is suddenly brought to rest by closing of the valve (d) the flow of fluid through the pipe is gradually brought to rest by closing of the valve 69. The maximum hydraulic efficiency of an impulse turbine is: 1 cos 1 cos 1 sin (a) (b) (c) 2 2 2
(d)
1 sin 2
70. If V1 and V2 are the velocities of water at inlet and outlet of the draft tube respectively, then the efficiency of a draft tube is: (a)
V1 V2 V1
(b)
V12 V12 2 V1
(c)
V1 V1 V2
(d)
V12 2
V1
V22
71. Penstock is a pipe carrying water from: (a) Turbine to tailrace (b) Intake to turbine (c) Reservoir to intake (d) None of the above 72. Breaking jet in an impulse turbine is used: (a) to break the jet of water (b) to bring the runner to rest in a short time (c) to change the direction of runner (d) none of the above
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73. ---------------- turbine is an axial flow turbine. (a) Francis (b) Pelton (c) Banki
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(d) Kaplan
74. If ‘A’ is the area of C / S of the piston, ‘N’ is the speed of the crank in r.p.m and ‘r’ is the radius of the crank, then the theoretical discharge of a single acting pump will be Ar N 2A r N 2A r (a) A r N (b) (c) (d) 60 60 60 75. A multistage pump is used to: (a) give high discharge (c) pump viscous fluids
(b) produce high heads (d) pump chemicals
END OF THE PAPER
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