Appsc 2012 Fluid Mechanics and Machinery

7/28/2019 Appsc 2012 Fluid Mechanics and Machinery

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APPSC Model Exam CE/ME

ACEEngineering Academy

APPSC 2012 (Model Exam)SUB: FLUID MECHANICS & MACHINERY

Branch: Civil & Mechanical Engineering

Time : 75 Minutes Maximum Marks : 75

1. One cubic meter of water weighs

(a) 100 liters (b) 250 liters (c) 500 liters (d) 1000 liters

2. Mercury does not stick to glass surface because(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 if shear rate is proportional to the shear stress the fluid is is known as

(a) Reynold fluid (b) viscous fluid

(c) Rigid fluid (d) Newtonian fluid

4. Given = 0.06 poise and = 0.9 gm/cm3

, what is the value of kinematic viscosity instokes?

(a) 0.04 (b) 0.054 (c) 0.066 (d) 0.082

5. A Jet of water issuing from a nozzle with a velocity 20m/s hits a flat plate moving away

from it at 10m/s. The cross-sectional area of the jet is 100cm2. What is the force on the

plate?

(a) 100N (b) 10 N (c) 10000 N (d) 1000 N

6. Consider the stream function = 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 pipe carries 70 lit/s of oil (sp.gr. = 0.75). At a section 62 cm above the

datum, the pressure is 2 cm vacuum of mercury (sp. gr. = 13.6). Assuming kinetic energy

correction factor of 1.1, what is the total head in m of oil at the section?

(a) 1.057 (b) 1.137 (c) 1.148 (d) 1.228

8. In flow over a V-notch, how much error in the computation of discharge over the notch

would arise from an error of 1% in the measurement of head over the notch?

(a) 1% (b) 1.5 % (c) 2% (d) 2.5%


2/8

ACE :: 2 :: ACE


9. All minor losses in a 15cm diameter pipeline add up to

g2

V16 2. What is the equivalent

length of a pipeline of same diameter with Darcys f = 0.03 for this condition?

(a) 160 m (b) 80 m (c) 20 m (d) 9 m

10. A buoy 2m3

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- 412 (b) 4312

(c) 3124 (d) 4213

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?

(a)

cos

d4(b)

d4

cos

(c)d

cos4

(d)

cos4

d

Where

is specific weight of the liquid ; is the relevant angle is surface tension of the liquid in the tube.

14. Surface tension of fluids is expressed as

(a) N/m (b) J/ m2

(c) Both (a) & (b) (D) N-m2

15. A fluid has a kinematic viscosity of four stokes and a specific gravity of three. Then the

viscosity of the fluid, in N.s/m2

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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ACE :: 4 :: ACE


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

density 1.2kg/m3

. If the head difference in vertical U-tube filled water is 12 mm, then thevelocity of air (in m/s) will be:

(a) 10.72 (b) 13.72 (c) 17.38 (d) 14.00

32. A jet of oil (RD = 0.8) has an area of 200cm2

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 VAVK 2 where K is equal to:(a) 3/2 (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 increased 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) Eulers (b) Bernoullis (c) Hagens (d) Navier-Stokes

39. Moodys charts are the graphical presentation between:

(a) Reynolds number and pressure head (b) Velocity and Reynolds number

(c) Friction factor and velocity of fluid (d) Friction factor and Reynolds 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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ACE :: 5 :: ACE


41. The head over 900

Vnotch 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 (b) Subsonic flow

(c) Transonic 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 (b) run-off river plant

(c) peak load 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 (c) 18-22 (d) more than 30

52. The shaft of a Kaplan runner is generally kept

(a) horizontal (b) vertical (c) inclined (d) anything

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

(d) K D1

B1

U1


6/8

ACE :: 6 :: ACE


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 headhead loss in pen stock

(d) gross headhead loss in pen stockvelocity head at turbine exit.

59. Cavitation occurs in

(a) Impulse turbine (b) Reaction turbines

(c) both (a) and (b) (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)

(a) WQH2/P (b) WQ

2H/75P (c) WQH/ 75 P (d) WQH/125 P

63. A reservoir has a head of 40 m and discharging 34 m3/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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ACE :: 8 :: ACE


73. ---------------- turbine is an axial flow turbine.

(a) Francis (b) Pelton (c) Banki (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

(a) A r N (b)60

NrA(c)

60

NrA2(d)

60

rA2

75. A multistage pump is used to:

(a) give high discharge (b) produce high heads

(c) pump viscous fluids (d) pump chemicals

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Appsc 2012 Fluid Mechanics and Machinery