BEng (Hons) in Civil and Infrastructure Engineering
Bridging Programme
Fundamental of Hydraulics and Fluid Mechanics
Bridging Assignment
Important Information for Students
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The criteria each task relates to are shown against that task where possible.
Please note that plagiarism is treated as a serious offence and therefore the work you
produce must be individual and original although may work in groups in some instances.
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Assume reasonable values for any data not given in. Clearly state such assumptions made
on the report.
REPORT STRUCTURE
a) Paper Size
A4
b) Margins LHS; RHS
25 mm
c) Basic Font Size
11 Point
d) Line Spacing
1.5
e) Fonts
Arial
f)
PDF Document
Presented
g) Word Limit
N/A
Question 01:
A. Explain the construction of a manometer to measure the pressure inside the fluid conveying
pipe that buried to the ground (stating that what are the important steps to be followed,
theory behind the system, importance of mercury) assuming that a proper technique is
used to avoid the mercury enters to the pipe. (10 Marks)
B. A 4 m long curved gate located in the side of a reservoir containing water as shown in figure
1.1. Carry out calculations to find the magnitude and position of force on the following
segments (15 Marks)
a. Vertical side wall only
b. Horizontal base having 6m width
c.
Curved surface using horizontal and vertical component.
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Figure 1.1
Question 02.
A. Show that the pressure due to a liquid column of density ρ and height h is given by ρgh,
where g is the acceleration due to gravity. (3 Marks)
Figure 2.1
B. Figure 2.2 shows a rigid rectangular block completely submerged in a liquid of density ρ.
The upper and lower surfaces of the block are at depths h 1 and h2 respectively from the
liquid surface. The atmospheric pressure is p0.(12 Marks)
Figure 2.2
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a. State the respective pressure acting on the upper and lower surfaces of the block
and hence show that the pressure difference between the two surfaces is given by
ρg(h2 – h1).
b. If the block is submerged slightly deeper into the liquid, would this pressure
difference change? Explain.
c.
Show that the pressure difference found in (b)(i) is consistent with the result
deduced from Bernoulli’s principle.
C. A rectangular aluminium block with a cavity at its center is completely submerged in water
as shown in Figure 2.3. The dimensions of the block are 10 cm x 8 cm x 6 cm. The densities
of aluminum and water are 2700 kg m-3 and 1000 kg m-3 respectively. The mass of air in the
cavity can be neglected. (10 Marks)
Figure 2.3
The block is able to stay at rest uprightly in water as shown in Figure 3.3.
a. Draw and label the force(s) acting on the aluminium block in Figure 2.3
b. Deduce the weight of the aluminium block using the pressure difference found in
(b)(i). Hence, find the volume of the cavity.
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Question 03.
A. The intake in Fig. 3.1 has cross-sectional area of 0.74 m2 and water flow at 0.40 m/s. At the
outlet, distance D = 180 m below the intake, the cross-sectional area is smaller than at the
intake and the water flows out at 9.5 m/s into equipment. What is the pressure difference
between inlet and outlet?(10 Marks)
Figure 3.1
B. In Figure 3.2, the fresh water behind a reservoir dam has depth D = 15 m. A horizontal pipe
4.0 cm in diameter passes through the dam at depth d =6.0 m. A plug secures the pipe
opening. (15Marks)
a. Find the magnitude of the frictional force between plug and pipe wall.
b. The plug is removed. What water volume exits the pipe in 3.0 h?
Figure 3.2
Question 04
C. A venturi meter is used to measure the flow speed of a fluid in a pipe. The meter is
connected between two sections of the pipe (Figure 4.1; the cross-sectional area A of the
entrance and exit of the meter matches the pipe’s cross-sectional area. Between the
entrance and exit, the fluid flows from the pipe with speed V and then through a narrow
“throat” of cross- sectional area a with speed v. A manometer connects the wider portion of
the meter to the narrower portion. The change in the fluid’s speed is accompanied by a
change ∆p in the fluid’s pressure, which causes a height difference h of the liquid in the two
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arms of the manometer. (Here ∆p means pressure in the throat minus pressure in the pipe.)
(25 Marks)
a. By applying Bernoulli’s equation and the equation of continuity to points 1 and 2 in
Figure 3.2, show that
where r is the density of the fluid.
b. Suppose that the fluid is fresh water, that the cross-sectional areas are 64 cm in the
pipe and 32 cm2 in the throat, and that the pressure is 55 kPa in the pipe and 41 kPa
in the throat. What is the rate of water flow in cubic meters per second?
Figure 4.1
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