B.E-B.E Civil Engineering Mechanics of Fluids (Sathyabama University, Chennai, Tamil Nadu-2011)
Monday, 19 August 2013 11:56Duraimani
(Established under section 3 of UGC Act,1956)
Course & Branch :B.E - P-CIVIL
Title of the Paper :Mechanics of Fluids Max. Marks:80
Sub. Code :SCIX1004 (2010-11) Time : 3 Hours
Date :05/12/2011 Session :FN
PART - A (10 x 2 = 20)
Answer ALL the Questions
1. Differentiate between specific weight and specific volume of a fluid.
2. State the Newton's law of viscosity and give examples of its applications.
3. Define the terms buoyancy and centre of buoyancy.
4. What do you understand by Total Pressure and Centre of Pressure?
5. Explain the terms: (a) Stream line (b) Stream tube
6. Define the following and give one practical example for each :
(a) Laminar flow (b) Turbulent flow
7. What is Euler's equation of motion? For the Euler's equation of motion, which forces are taken into consideration?
8. State Bernoulli's theorem for steady flow of an incompressible fluid.
9. Explain the term dimensionally homogeneous equation.
10. Give the dimensions of
(a) Force (b) Viscosity (c) Power (d) Kinematic viscosity.
PART – B (5 x 12 = 60)
Answer ALL the Questions
11. The dynamic viscosity of an oil, used for lubrication between a shaft and sleeve is 6 poise. The shaft is of diameter 0.4m and rotates at 200rpm. Calculate the power lost in the bearing for a sleeve length of 90mm. The thickness of the oil film is 1.6mm.
(or)
12. Two large plane surfaces are 2.4cm apart. The space between the surfaces is filled with glycerin. What force is required to drag a very thin pate of surface area 0.6 square meter between the two large plane surfaces at a speed of 0.6 m/sec, if,
(a) the thin plate is in the middle of the two plane surfaces, and
(b) the thin plate is at a distance of 0.8 cm from one of the plane surfaces?
Take the dynamic viscosity of glycerin = 8.10 x 10-1 N-s/m2.
13. A differential manometer is connected at the two points A and B of two pipes. The pipe A contains a liquid of sp.gr. = 1.5 while pipe B contains a liquid of sp. gr. = 0.9. The pressures at A and B are 1kgf/cm2 and 1.80kgf/cm2 respectively. Find the difference in mercury level in the differential manometer.
(or)
14. Find the magnitude and direction of the resultant water pressure acting on a curved face of a dam which is shaped according to the relation y= (x2 / 9). The height of the water retained by the dam is 10m. Consider the width of the dam as unity.
15. Water flows through a pipe AB 1.4m diameter at 3m/s and then passes through a pipe BC 1.7m diameter. At C, the pipe branches. Branch CD is 1m in diameter and carries one-third of the flow in AB. The flow velocity in branch CE is 2.5m/s. Find the volume rate of flow in AB, the velocity in BC, the velocity in CD and the diameter of CE.
(or)
16. In a two - dimensional incompressible flow, the fluid velocity components are given by, u= x - 4y and v = - y - 4x.
Show the velocity potential exists and determine its form. Find also the stream function.
17. Find the discharge of water flowing through a pipe 30cm diameter placed in an inclined position where a venturimeter is inserted, having a throat diameter of 15cm. The difference of pressure between the main and throat is measured by a liquid of sp.gr. 0.6 in an inverted U - tube which gives a reading of 30cm. The loss of head between the main and throat is 0.2 times the kinetic head of the pipe.
(or)
18. A window, in a vertical wall, is at a distance of 30m above the ground level. A jet of water, issuing from a nozzle of diameter 5cm, is to strike the window. The rate of flow of water through the nozzle is 3.5m3/min. and nozzle is situated at a distance of 1m above ground level. Find the greatest horizontal distance from the wall of the nozzle so that jet of water strikes the window.
19. A ship 300m long moves in sea-water, whose density is 1030kg/m3. A 1:100 model of this ship is to be tested in a wind tunnel. The velocity of air in the wind tunnel around the model is 30m/s and the resistance of the model is 60N. Determine the velocity of ship in sea-water and also the resistance of the ship in sea-water. The density of air is given as 1.24 kg/m3. Take the kinematics viscosity of the sea water and air as 0.012 stokes and 0.018 stokes respectively.
(or)
20. (a) State Buckingham Pi theorem . (4)
(b) Define the following non dimensional numbers (8)
i) Reynolds number
ii) Froude number
iii) Euler number
iv) Weber number
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