MU Mechanical Engineering (Semester 4)
Fluid Mechanics
December 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

1 (a) Define a fluid and distinguish between ideal and real fluids.
5 M
1 (b) A stone weights 2KN in air and 168N in water. Calculate the volume and specific gravity.
5 M
1 (c) Explain Hydrostatic law.
5 M
1 (d) Define steam lines, path lines and streak lines.
5 M
1 (e) Define Mach number, stagnation density and stagnation temperature.
5 M

2 (a) The velocity components in two dimensional flow fields are as follows
u=y3/3+2x-x2y, v=xy2-2y-x3/3.
i) whether the flow is possible
ii) obtain an expression for steam function
iii) obtain an expression for potential function.
10 M
2 (b) A sliding gate 3m and 1.5m high situated in a vertical plane has a coefficient of friction between itself and guide of 0.18. If the gate weight is 19n and its upper edge is at a depth of 9m, what vertical force is required to raise it? Neglect buoyancy force on gate.
10 M

3 (a) Starting from the Navier Stokes equation for an incompressible Newtonian fluid derive Bernoulli's equation starting the assumptions.
10 M
3 (b) Derive the expression for stagnation density and stagnation temperature.
10 M

4 (a) A pipeline of length 2400m is used for power transmission. If 115KW power is to be transmitted through the pipe in which water having a pressure of 500 N/cm2 at inlet is flowing? Find the diameter of the pipe and efficiency of transmission if the pressure drop over the length of pipe is 100 N/cm2. Take f=0.026 also find diameter if pipe corresponding to maximum efficiency of transmission.
10 M
Write short note on.
4 (b) (i) Moody's diagram
5 M
4 (b) (ii) Major and minor losses.
5 M

5 (a) A normal shock wave occurs in a duct in which air is flowing at a Mach number of 1.5. The static pressure and temperature upstream of the shock wave is 1.5 bar and 270°C. Determine pressure, temperature and mach number downstream of the shock. Also calculate strength of shock.
10 M
5 (b) Explain Prandtl's mixing length theory.
10 M

6 (a) The velocity profile within a laminar boundary layer over a flat plate is given by the equation.
u/U =2(y/δ) - (y/δ)2
Where U is the mean stream velocity and δ is the boundary layer thickness. Determine the displacement thickness and momentum thickness.
10 M
Explain
6 (b) (i) Aerofoil theory
5 M
6 (b) (ii) Reynolds Transportation theorem.
5 M

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