# SULTAN QABOOS UNIVERSITY

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24 Οκτ 2013 (πριν από 4 χρόνια και 6 μήνες)

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SULTAN QABOOS UNIVER
SITY

Department of Civil Engineering

B.Eng. Examinations, Fall Semester 2003

FLUID MECHANICS

CIVL 4046

December 23, 2003

9:00
-
12:00

The following is provided for this examination

Candidates are permi
tted to bring into the examination room

Calculator (programmable or non
-
programmable).

Class notes and textbook

Instructions to candidates:

The paper consists of FIVE questions.

Attempt all the questions.
FLUID MECHANICS

CIVL 4046

Time allowed: 3

hours

Attempt all the questions.

1
. A 25
-
mm diameter shaft is pulled through a cylindrical bearing as shown below.

The lubricant that fills the 0.3
-
mm gap between the shaft and bearing is an oil having
a kinematic viscosity of 0.
0008 m
2
/s and a specific gravity of 0.91. Determine the
force P required to pull the shaft at a velocity of 3 m/s. Assume the velocity
distribution in the gap is linear.

[15%]

2.

A rectangular sluice door as shown below, is hinged at the top at
A and kept closed
by a weight fixed to the door.

The door is 120
-
cm wide and 90
-
cm long and the center of gravity of the complete
door and weight is at G, the combined weight being 9810 N. Find the height of the
water
h

on the inside of

the door which will just cause the door to open.

[25%]

3.

A closed tank of fixed volume is used for the continuous mixing of two liquids
which enter at A and B are discharged completely mixed at C. The diameter of the
inlet pipe at A is 150
-
mm and the l
iquid flows in at the rate of 0.056 m
3
/s and has a
specific gravity of 0.93. At B the inlet pipe is 100
-
mm diameter, the flow rate is 0.03
m
3
/s and the liquid has a specific gravity of 0.87. If the diameter of the outlet pipe at
C is 175
-
mm, what will be t
he mass flow rate, velocity and specific gravity of the
mixture discharged?

[20%]

50 cm

P

shaft

bearing

lubricant

h

G

A

30cm

W

B

60
o

4.
A jet of water from a nozzle is deflected through an angle of 60 degrees from its
original direction by a curved vane, which it enters tangentially (shown
below)
without shock with a mean velocity
v
1

of 30 m/s and leaves with a mean velocity
v
2

of
25m/s.

If the mass flow rate from the nozzle is 0.8 kg/s, calculate the magnitude and
direction of the resultant force on the vane if the vane is stat
ionary.

[20%]

5.
A venturi meter having a throat 100
-
mm in diameter is fitted in a pipeline 250
-
mm
in diameter through which oil of specific gravity 0.9 is flowing at the rate of 0.1
m
3
/s.
The inlet and the throat of the meter are connected differentiall
y to a U
-
tube
manometer containing mercury of specific gravity 13.6 with oil immediately above
this. Starting from Bernoulli’s equation find the coefficient of discharge for the meter
if the difference in mercury levels is 0.63 m.

[20%]

v
1

v
2

60
o

Fixed vane