Code No: 07A3EC02 Set No. 4
II B.Tech I Semester Regular Examinations, November 2008
FLUID MECHANICS AND HYDRAULIC MACHINERY
( Common to Electrical & Electronic Engineering and Production
Time: 3 hours Max Marks: 80
Answer any FIVE Questions
All Questions carry equal marks
⋆ ⋆ ⋆ ⋆ ⋆
1. (a) Define dynamic viscosity and kinematic viscosity. What are their units? Ex-
plain the significance of viscosity on fluid motion.
(b) Find the pressure in N/m2 represented by a column of
i. 10cm of water
ii. 5 cm of oil of relative density 0.75
iii. 2cm of mercury. [8+8]
2. (a) Derive the equation of continuity in dierential form.
(b) Determine whether the following velocity components satisfy the continuity
i. u = 2x2 + zy, v = −2xy + 3y3 + 3zy, w = −3/2 z2
− 2xy − 6yz
ii. u = −cx/y, v = c log xy. [6+10]
3. (a) Explain how do you measure the velocity of flowing water in a stream using
(b) An oil of relative density 0.90 flows through a vertical pipe of diameter 20cm.
The flow is measured by a 20cm × 10cm venturimeter. The throat is 30cm
above the inlet section. A dierential U tube manometer containing mercury
is connected to the throat and the inlet. If coecient of discharge is 0.99 what
is the manometer reading for a flow of 50lit/sec. [6+10]
4. (a) A 15 cm diameter jet of water with a velocity of 20 m/sec strikes a plate
normally. If the plate is moving with a velocity of 8m/sec in the direction of
the jet, calculate the work done per second on the plate and the eciency of
the energy transfer.
(b) Prove that the force exerted by a jet of water on a fixed hemispherical curved
vane when the jet strikes at the centre is F = ρav2 where
ρ = Mass density of water
a = Area of cross section of the jet
v = Velocity of the jet. [8+8]
5. (a) What are valves used in a penstock. Explain with neat sketches, various types
of valves with their suitability under various conditions.
(b) What is intake structures. Explain dierent types with the help of neat
6. (a) How will you classify the turbines? Explain
(b) A Pelton wheel is to be designed for the following specifications. Power
=735.75 kW S.P. Head = 200 m, Speed = 800 r.p.m., η0 = 0.86 and jet
diameter is not to exceed one-tenth of the wheel diameter. Determine :
i. Wheel diameter,
ii. The number of jets required, and
iii. Diameter of the jet. Take Cv = 0.98 and speed ratio = 0.45. 
7. (a) What is cavitation? How can it be avoided in reaction turbine?
(b) What is governing and how it is accomplished for dierent types of water
8. (a) Draw an indicator diagram, considering the eect of acceleration and friction
in suction and delivery pipes. Find an expression for the work done per second
in case of single-acting reciprocating pump.
(b) A single-acting reciprocating pump having a bore of 150 mm and a stroke of
300 mm is raising water to height of 20 m above the sump level. The pump
has an actual discharge of 0.0052 m3/s. The eciency of the pump is 70%. If
the speed of pump is 60 r.p.m. Determine:
i. Theoretical discharge
ii. Theoretical power
iii. Actual power, and
iv. Percentage slip. [8+8]