 MORE IN Fluid Mechanics 1
SPPU Civil Engineering (Semester 4)
Fluid Mechanics 1
May 2015
Total marks: --
Total time: --
INSTRUCTIONS
(1) Assume appropriate data and state your reasons
(2) Marks are given to the right of every question
(3) Draw neat diagrams wherever necessary

Answer any one question from Q1 and Q2
1 (a) Define:
i) Mass density
ii) Specific gravity
iii) Surface tension
iv) Capillarity
v) Specific weight
vi) Specific volume.
6 M
1 (b) A circular plate 2.95 m diameter is immersed in water in such a way that greatest and least depth below the free surface is 4.1 m and 1.6 m respectively. Determine the total pressure on one face of the plate and position of centre of pressure.
6 M

2 (a) State Buckingham's π theorem. Explain the procedure for solving problems by Buckingham's π theorem.
6 M
2 (b) A rectangular pontoon is 5m long, 3m wide and 1.20 m high. The depth of immersion of the pontoon is 0.85 m in sea water. If the centre of gravity is 0.65 m above the bottom of the pontoon, determine the meta-centric height. Take density of sea water=1025 kg/m3.
6 M

Answer any one question from Q3 and Q4
3 (a) Explain:
ii) Uniform flow and Non-uniform flow
iii) Laminar flow and Turbulent flow.
6 M
3 (b) Derive the Bernoulli's equation. Also mention the assumptions made for it.
6 M

4 (a) Explain rotation and vorticity. Derive the rotational components for three-dimensional flow.
6 M
4 (b) A 20cm × 10cm venturimeter is inserted in a vertical pipe carrying oil of specific gravity 0.8, the flow of oil is in upward direction. The difference of levels between the throat and inlet section is 55 cm. The oil mercury differential manometer gives a reading of 33 cm of mercury. Find the discharge of oil in liters/s. Neglect losses.
6 M

Answer any one question from Q5 and Q6
5 (a) Explain with neat sketches 'boundary layer separation and its control'
7 M
5 (b) In Case of laminar flow, through a circular pipe, show that ratio of maximum velocity to average velocity=2.0.
6 M

6 (a) A fluid of viscosity 0.7 N.s/m2 and specific gravity 1.3 is flowing through a circular pipe of diameter 100 mm. The maximum shear stress at the pipe wall is given as 196.2 N/m2. Find:
ii) The average velocity
iii) Reynolds number of the flow.
7 M
6 (b) Find the displacement thickness, the momentum thickness and energy thickness for the velocity distribution in the boundary layer given by u/U=y/δ, where u is the velocity at a distance y from the plate and u=U at y=δ, where δ=boundary layer, thickness.
6 M

Answer any one question from Q7 and Q8
7 (a) Explain in brief:
i) Instantaneous velocity
ii) Temporal mean velocity
iii) Scale of turbulence.
6 M
7 (b) Derive the expression for ?oss of head due to sudden enlargement?in case of flow through a pipe.
7 M

8 (a) The rate of flow of water through a horizontal pipe is 0.25 m3/s. The diameter of the pipe which is 200 mm is suddenly enlarged to 400 mm. The pressure intensity in the smaller pipe is 11.772 N/cm2. Determine:
i) Loss of head due to sudden enlargement
ii) Pressure intensity in the large pipe
iii) Power lost due to enlargement.
7 M
Explain in brief with neat sketches:
8 (a) (i) Prandtl's mixing length theory.
3 M
8 (a) (ii) Velocity distribution in turbulent flow.
3 M

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