Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 1 of 9
Exam information
Course code and title
CIVL2131
Environmental Fluid Mechanics
Semester Semester 2, 2021
Exam type Online, invigilated, closed book, end-of-semester examination
Exam technology Zoom invigilated, Hand written examination
Exam date and time
Refer to your personal exam timetable for the scheduled date and time of this exam.
The examination duration from the time your invigilator starts your examination is: 2 hours
10 minutes including 10 minutes planning time.
Up to 15-minutes is available at the end of the examination to enable you to submit your
examination. This is not extra working time.
If your examination is submitted after the 15 minute submission time, a late penalty will
apply unless you can provide evidence that the late submission was beyond your control.
Refer to the Important exam condition information below for further details.
Exam window
The exam window includes the on-boarding process, planning time, the examination writing
time and the submission time.
After an on-boarding process (e.g. where your ID is checked and you are given instructions on
how the exam will proceed), your invigilator will start the exam. You will then have the
duration of the exam listed to complete your exam.
Please note: It may take some time to start your examination, however your exam timer
does not start until your invigilator starts your exam.
Permitted materials
This is a Closed Book examination - specified written materials permitted
 Unannotated Bilingual dictionary
 One A4 sheet of handwritten notes double sided
Casio FX82 series or UQ approved (labels not required).
Here is the list of UQ approved calculators.
Essential equipment
A PC or laptop with a single (one) screen and functional microphone and speakers.
A standalone webcam.
A device capable of scanning. You are not permitted to use your phone/scanner until the
invigilator tells you that you may use it to submit your examination.
Recommended
equipment
A printer/scanner.
Instructions
You will need to download the question paper included within the Blackboard Test. Complete
the examination by hand on blank paper, photograph and upload the completed exam
answers file to the Blackboard assignment submission link.
If you are not printing the exam paper, write ALL answers on blank paper, clearly writing your
student name and number on the first page and labelling each question.
If you are printing the exam paper, write ALL answers on the exam paper in the space
provided.
Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 2 of 9
Answers or working on rough paper will NOT be assessed.
Upload a single PDF file containing all your answers to the assignment submission link.
To create the single PDF file you can either:
 scan all your working and save as a single PDF file, or
 take photos of each page and create a single PDF using an app on your phone.
Creating a PDF from photos:
There are a number of apps that can do this, here are just two:
 https://apps.apple.com/au/app/genius-scan-pdf-scanner/id377672876
 https://www.google.com/photos/scan/
To avoid large file sizes, you must scan handwritten answers to a PDF file and must NOT
submit as an image (e.g. .JPEG). Large files take longer to upload and this can have an impact
on your submission time.
Who to contact
Because this is an online examination, it may not be possible for the Course Coordinator to
respond to individual students’ questions about the examination the way they could if
students were sitting the examination on Campus. Given the nature of this examination,
effectively responding to student queries and/or relaying corrections to exam content during
the exam may not be feasible.
However, the following is possible:
 Use the Zoom chat function to ask the invigilator a question.
 Specify any assumptions you may have made while answering a particular question
(be sure to reference the particular question/s)
If you experience any technical difficulties when connected to an invigilator, talk to your
online invigilator via the chat functions.
If the technical trouble cannot be resolved, you should document any technical advice
provided to you.
If your invigilator advises you to contact the University or you experience any technical
difficulties such as losing a connection to the Zoom session, contact the Library AskUs service
for advice as soon as practicable:
Chat: support.my.uq.edu.au/app/chat/chat_launch_lib
Phone: +61 7 3506 2615
Email: examsupport@library.uq.edu.au
If you find, due to technical issues, your online exam submission is late, you may apply for
exemption of the late penalty.
You must apply for an exemption no later than 24 hours after the exam due date and time
via my.UQ.
Important exam
condition
information
Academic integrity is a core value of the UQ community and as such high academic integrity
expectations apply to all examinations, whether undertaken face-to-face or online.
This means:
 You are only permitted to access the allowed resources during this closed book
exam.
 You are not permitted to consult any other person – whether directly, online, or
through any other means – about any aspect of this examination during the
examination window.
 If it is found that you have given or sought outside assistance with this examination,
Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 3 of 9
then that will be deemed to be cheating and you will be issued with an allegation of
misconduct.
 You are required to use a microphone and speaker and not a headset or earbuds
 You are required to have a camera that allows the invigilator to see that you are not
using outside materials or communicating with others.
 You will be asked to use your camera to show your work area to your invigilator
before commencing your examination.
 If during the examination your work area is not visible you will be asked to
reposition the camera so that the work area is visible.
Undertaking this online examination deems your commitment to UQ’s academic integrity
pledge as summarised in the following declaration:
“I certify that I have completed this examination in an honest, fair and trustworthy manner,
that my submitted answers are entirely my own work, and that I have neither given nor
received any unauthorised assistance on this examination”.
If you submit your online exam late, the following penalties will be applied to the total mark
available for the assessment:
 Less than 5 minutes – 5% penalty
 From 5 minutes to less than 15 minutes – 20% penalty
 More than 15 minutes – 100% penalty
These penalties will be applied unless you provide sufficient evidence of problems with the
system and/or process that were beyond your control.

Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 4 of 9
Q1. 30%. Write answers (symbolic and numerical) and show your key working steps at the end
of your answers.

The figure below shows a side elevation view of a plane and straight dam fuse gate that slopes at
45 degrees, which has a width B=5m into the paper. The gate holds back water of depth D. The
gate pivots about a hinge at (x,y)=(0,0) and is restrained by pins at the top (which are not relevant
to the problem). Neglect the self-weight of the gate. The dotted line shown is relevant to part d)
only.



a) Draw the pressure diagram for the gate (draw it on the figure and space above if you have
printed the exam paper) (5%)

b) Write a symbolic expression for the horizontal force on the gate and evaluate it for D=4m. (10%)





c) Write a symbolic expression for the vertical force on the gate and evaluate it for D=4m. (10%)






d) If the gate was curved (dotted line), instead of straight, state if the horizontal and vertical forces
are the same as in parts b and c, or different, and explain why. Use diagrams as appropriate. No
numerical calculations are required. (5%)




D
y
x
z
Water
surface
Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 5 of 9

Show key working steps for Q1 only. Include diagrams as appropriate. There is no need to show
all working.















































Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 6 of 9
Q2. 35%. Write answers (symbolic and numerical) and show your key working steps at the end
of your answers.

A pipeline in a flooded quarry supplies a flow to a jet pump used to extract sand from another part
of the quarry bed. The pipeline has diameter Dp=0.5m and a total length 500m from intake to
nozzle. The diameter of the jet nozzle Dj=is 0.1m and the exit velocity of the jet is Uj. The pipes are
steel, ks=0.1mm. =1025kg/m3, =110-3Ns/m2. The intake and nozzle are at the same elevation.
The discharge is Q=0.55m3/s. In total there are three 90 bends k90=0.8, and a valve.


a) Using s as the distance along the pipe (from intake to nozzle), sketch the energy and
piezometric lines for the system, (use the space below if you have printed the exam paper).
Assume atmospheric pressure at the water surface. (5%)

b) Including all losses, specify the pump head required to achieve the stated discharge. (15%)



c) With the loss coefficient given, find the force on the valve. Note that the absolute or gage
pressure in the pipe are not needed to answer this question. (5%)


d) Specify the pipe diameter required to carry a flow of Q=0.55m3/s over a distance L=1000m
when the head loss must be limited to 70m. Use a steel pipe with ks=0.1mm. Ignore local losses.
State the friction factor and Reynolds number. This part is not related to parts a)-c). (10%)



Nozzle

Intake, ke=0.2

Pipeline



Valve, kv=0.6
s
H
Pump


Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 7 of 9
Show key working steps for Q2 only. Include diagrams as appropriate. There is no need to show
all working.















































Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 8 of 9
Q3. 35 %. Write answers (symbolic and numerical) and show your key working steps at the end
of your answers.

A sphere is tested for drag resistance in a wind tunnel. A pressure tapping at the stagnation point
is attached to an inclined air/kerosene manometer, with the other end of the manometer
attached to a static pressure tapping on the side of the tunnel. The static pressure tapping
removes the effect of the air pressure inside the wind tunnel, so that only the stagnation pressure
is measured.
The kerosene has density k.





a) Neglecting the air density, write a symbolic expression for the stagnation pressure, pst, in terms
of k, g, y and . Find the wind velocity in the tunnel when (k, y, , air)=(780kg/m3, 0.04m, 30,
1.2kg/m3). (15%)




b) Engineers designing roofing materials need to find the terminal velocity of a spherical (V=πD3/6)
hailstone of diameter D=38mm and with specific gravity s=0.95, falling in air with (air,
air)=(1.2kg/m3, 1.810-5Pa.s). Give the velocity, Reynolds number and drag coefficient in the
space below. (10%)



c) Find the dimensionless groups describing the terminal velocity, U, for a sphere if the dependent
variables are: diameter, D, sphere density, s, fluid density, f, fluid viscosity, , and gravity. Find
the number of groups and their form. Use the table below. (10%).

D
g
s
f

U
Semester Two Final Examinations, 2021 CIVL2131 Environmental Fluid Mechanics
Page 9 of 9
Show key working steps for Q3 only. Include diagrams as appropriate. There is no need to show
all working.















































END OF EXAMINATION
Tables of dimensions, charts and formulae sheet follow





TEB, CIVL2131

Environmental Fluid Mechanics Formulae Sheet

Application Equation Comments


Compressibility and gas law


Newton’s Law of viscosity

Hydrostatic pressure (incompressible)

Centre of pressure

Metacentric height

Continuity

Momentum


Energy


Discharge equation


Stream power

Euler equation


Reynolds number (pipe)

Froude number


Parallel flow


Parabolic flow profile (pipe)


Head loss in a pipe


Friction

2211 UAUAQ ==
)( 12 UUQF −=∑ ρ
22
0 8
UfkU ρτ ==
Kp
ρρ
=
∂
∂ RTp ρ=
dy
du
A
F µτ ==
constgzp +−= ρ
Ay
Iyy Gcp +=
gL
UFr =
subV
IBM 00=
Hz
g
U
g
pz
g
U
g
p
∆+++=++ 2
2
22
1
2
11
22 ρρ
hgKQ ∆= 2
1
2
2
1
1
−




=
A
A
AC
K d
gQHρ
x
p
x
uu
t
u
∂
∂
−=





∂
∂
+
∂
∂ρ
µ
ρUD
=Re
ys
zp
∂
∂
=
∂
+∂ τγ )(













−=
2
max 1 R
rUu
max2
1UU =
D
L
g
h f ρ
τ 04=
g
UK
D
L
g
UfhL 22
22
+=
TEB, CIVL2131


Colebrook-White



Fully rough turbulent flow


Local losses


Network correction


Drag, Lift and skin
friction forces

Strouhal number

Morison equation


Pressure coefficient


Slow reservoir discharge




Unsteady energy equation


Surge pressure

Accelerating flow



Surge tower



Velocity of sonic wave



Water hammer pressure








+−=
fD
k
f H
s
Re
51.2
71.3
log21
14.1log21 +





=
s
H
k
D
f
2
1
2
2
2 1
2 






−=
A
A
g
U
hLg
UUKhL 2
)( 221 −=
∑
∑−=
||2 0
2
0
ii
ii
QK
QK
Qδ
AUCF DD
2
2
1 ρ= AUCF LL
2
2
1 ρ= BLUCF fs
2
2
1 ρ=
dt
dUVCUAUCF MD ρρ += 2
1
2
2
1 V
pCp
ρ
∆
=
( )






+
−
−=
2
0
1
0
12
/2
2
A
A
A
A
Cg
HH
t
dt
dU
g
Lhz
g
U
g
pz
g
U
g
p
L ++++=++ 2
2
22
1
2
11
22 ρρ
dt
dU
g
LH =δ






−
+
+
=
20
20
0
ln
)1( UU
UU
UK
Lt
Q
dt
dZAUA s += 0=±+ LhZdt
dU
g
L
t
LA
gA
gA
LA
A
QZ
s
s
s








= sin0
U
fDSt =
ρ
vEc =
tE
DK
cc p
+
=
1
1
ucpp ph ρδ == h
c
h pct