SUB: FLUID MECHANICS
MODULE: 63-66
TEST-6 _______________________________________________ __________________________________ _____________ ________________________________________ __________________________________ ______ _ 1.
A spillway 7.2 m high and 150 m long discharges 2150 under a head of 4 m. If a 1:16 model of the spillway is to be constructed, find the model discharge? a) 2.1 b) 4.2 c) 6.3 d) 1.4
(C) 38 8.
(D) 1440
A horizontal jet strikes a frictionless vertical plate (the plan view is shown in the figure). It is then divided into two parts, as shown in the
2.
3.
The height of hydraulic jump in a stilling pool of 1:25 scale model was observed to be 10cm. the corresponding prototype height of jump is a) 2.5 b)5.0 c) 4.0 d) 6.0
1850.5m/s
d)
2500.5m/s
A model of a reservoir having a free water surface within it is drained in 3 minutes by opening a fluice gate. The geometrical scale of the model is
6.
7.
1 and 3 only
30
(c) 45 (d) 60 The circulation 'G' around a circle of radius 2 units for the velocity field u = 2x + 3y and v = 2y is (a) -6 units (b) -12 units (c) 18 units (d) -24 units
d)
. The
equation of the stream line passing through the
d) 1, 2 and 3
If the pump head is 75m, discharge is 0.464
/s and the motor speed is 1440 rpm at rated condition, the specific-speed of the pump is about (A) 4
9.
(b)
dimensional flow is given as
Distorted models are needed for: 1. Rivers 2. Dams across wide rivers 3. Harbours a) 1 and 2 only b) 2 and 3 only c)
15
10. The velocity in m/s at a point in a two-
A river model is constructed to a horizontal scale of 1:1000 and a vertical scale of 1:100. A model discharge of 0.1 would correspond to a discharge in the prototype, of what magnitude? a) b) c)
(a)
. How long would it take to
empty the prototype a) 30 minutes b) 40 minutes c) 50 minutes d) 15 minutes 5.
? what is the value of
A 1:30 scale model of a submarine is to be tested in a wind tunnel for its drag when it is operating at 15Km/h in ocean. The kinematic viscosity of air is 1.51 and for water 1.02 . What is the velocity of air in wind tunnel that should be maintained for kinematic similarity? a) 1500m/s b) 2000m/s c)
4.
figure. If the impact loss can be neglected,
point is (a) 3dx-2dy=0 3dx+2dy=0 (d)
(b) 2x+3y=0 3xy=6
(c)
11. For a two dimensional flow field, the stream function
is given as ( ) . The
magnitude of discharge occurring between the stream lines passing through points (0,3) and (3,4) is: (A) 6 (B) 3 (C) 1.5 (D) 2 12. Two pipelines, one carrying oil (mass density 900 kg/m3) and the other water, are connected to a manometer as shown in the figure. By what amount the pressure in the water pipe should be increased so that the mercury levels in both the limbs of the manometer become equal? (Mass density of mercury = 13,550 kg/m3 and g = 9.81 m/s 2)
(B) 26
JH ACADEMY
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SUB: FLUID MECHANICS
MODULE: 63-66 18 mm. Determine the rate of flow if the coefficient of discharge for the weir is 0.56. a) b) c) d) 19. Determine the head on a 45 V-notch weir for a discharge of 225 L/s. a) 0.691 b) 0.346 c) 0.567 d) 0.987
(a) 24.7kPa (b) (c) 26.7 kPa (d)
26.5 kPa 28.9 kPa
13. The reading of differential manometer of a Venturimeter, placed at 45 to the horizontal is 11 cm. If the Ventruimeter is turned to horizontal position, the manometer reading will be. (a)
zero
(b)
cm √
(c) 11 cm (d) √ cm 14. A triangular open channel has a vertex angle to 90° and carries flow at a critical depth of 0.30 m. The discharge in the channel is (a) 0.08 m3/s (b) 0.11 m3/s (c) 0.15 m3/s (d) 0.2 m3/s 15. The normal depth in a wide rectangular channel is increased by 10%. The percentage increase in the discharge in the channel is: (A) 20.1 (B) 15.4 (C) 10.5 (D) 17.2 16. To determine the coefficient of velocity of a small circular sharp-edged orifice in the side of a vessel, the horizontal and vertical coordinates of the trajectory of the jet were measured for a head of 20 cm. The horizontal coordinate from vena contracta was found to be 86 cm whilst the vertical coordinate was 96 cm. Find the coefficient of velocity? a) 0.981 b) 0.876 c) 0.915 d) 0.872 e) 17. A cylindrical tank of diameter 1 m mounted on its axis contains a liquid which drains through a 2 cm diameter hole in the base of the tank. If the tank originally contains 1000 litres, determine the time taken for total drainage. The discharge coefficient for the hole may be taken as 0.6. a) 2120 s b) 1060 s c) 560 s d) 6040 s
18. The weir above a downcomer in the rectifying section of a distillation column has a breadth of 1.2 m over which liquid flows with a head of
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20. A jet of water 75 mm diameter having a velocity of 20 m/s, strikes normally a flat smooth plate. Determine the thrust on the plate if the plate is moving in the same direction as the jet with a velocity of 5 m/s. a) 995 N b) 875 N c) 345 N d) 675 N 21. The stream function for a two dimensional flow is given by . The resultant velocity at a point P(2,3) is a) 8.45 units/s b) 7.21 units/s c) 6.44 units/s d) 5.18 units/s 22. Given
and ( ) , the
discharge passing between the streamlines through the points (1,3) and (3,3) is a) 2 units b) 4 units c) 8 units d) 12 units 23. In the model of highway bridge constructed to a scale of 1:25, the force of water on the pier was measured to be 0.5 kg. The force on the prototype pier will be a) 7501.5 kg b) 7622.5 kg c) 7812.5 kg d) 7916.5 kg 24. The maximum permissible suction lift for centrifugal pump in practice is a) 12 m b) 10 m c) 6m d) 3m 25. Given that atmospheric pressure head = 9 m, vapour pressure head(max.)=1m, failure head = 40 m and cavitation coefficient , the height at which the turbine can be set above the tail race level is a) 6m b) 4m c) 3m d) 2m
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