FACULTY OF ENGINEERING TECHNOLOGY
DEPARTMENT OF CIVIL TECHNOLOGY ENGINEERING
COURSE CODE
BNP 10303
COURSE NAME
FLUID MECHANIC LABORATORY
TITLE
Flow Through Orifice with Hydraulic
Bench
1. AFIQ AFZAL BIN AB SOBI (CN240385)
2. MUHAMMAD HARRIS SHAZWAN BIN
ROSMAINOOR (CN240297)
3. NURSHAMIRA BINTI ZAKARIA (CN240153)
4. NUR SYAHMINA BINTI ABDUL
GROUP MEMBERS
MALEK(CN240166)
SECTION
1
SEMESTER
2024/2025
LECTURER’S
NAME
DR. NUR AINI BINTI MOHD ARISH @ ARSHAD
DATE OF SUBMIT
28/05/2025
1
STUDENT CODE OF ETHICS
FACULTY OF ENGINEERING TECHNOLOGY
DEPARTMENT OF CIVIL ENGINEERING TECHNOLOGY
I hereby declare that I have prepared this report with my own efforts. I also admit to not
accept or provide any assistance in preparing this report and anything that is in it is true.
1) Group Leader
Name: Afiq Afzal Bin Ab Sobi
Matrix No. : CN240385
Signature:
2) Group Member 1
Name: Muhammad Harris Shazwan Bin Rosmainoor
Matrix No. : CN240297
Signature:
3) Group Member 2
Name: Nurshamira Binti Zakaria
Matrix No. : CN240153
Signature:
4) Group Member 3
Name: Nur Syahmina Binti Abdul Malek
Matrix No. : CN240116
Signature:
2
Assessment
PO
SK
Rubric elements
Criteria
Subcriteria
SP
Description of the labwork:
objective and introduction
SK3
Explanation of principles and
theories
Perform labwork with correct
procedure and equipment
Level
0
SK4
Excellent
Good
Weight
Score
Comprehensive
description
5
0.6
3
2
3
P1
Lackor not related
description
Minimal description
Some description
shown
P2
Equipment or
procedurenot shown
Incorrect
equipment or
procedureshown
Correct equipment
but procedure briefly
shown
Correct equipment
and adequate
procedureshown
Correct equipment and
comprehensive
procedureshown
5
0.6
3
Lack of data
collection and no
calculation shown
Complete data
collection but no
calculation shown
Complete data
collection but
incorrectcalculation
shown
Complete data
collection and correct
calculation
Complete and correct
data collection and
calculation
5
0.4
2
Not concluding the
whole report
Minimalconclusion
of the whole report
Someconclusion of
the report shown
Adequateconclusion
of the whole report
Conciseconclusion of
the whole report
5
0.4
2
Correct and precise data
collection: results and calculation
PLO4 (Investigation)
Conduct investigations of
broadly-defined
problems; locate, search
and select relevant data
from codes, databases,
and literature, design
andconduct experiments
to provide valid
conclusions.
4
Rate
Adequate description
shown
5
SP1
Show thecorrect equipment and
procedure
Labwork (Written report)
1
Fair
SP4)
Poor
Demonstrate standard measurement techniques of fluid mechanics and their applications in order to solve fluid mechanics problems. (LOD4, PLO4, P5) (SK3, SK4, SK8) (SP1, SP3,
V.Poor
CLO3:
No Participation
Report Assessment Rubrics
Data collection, analysis, and
conclusion
SP3
P3
Concise conclusion
Discussion of the result, analysis,
and conclusion
None at all
SK8
Demonstration of analysis using
related relevant data from codes,
databases, and literature.
Analyse and discuss the data
trends using correct graphs
SP4
P4
Incorrect analyses
and discussion
Correctanalyses
with minimal
discussion
Correct analyses
withsome discussion
Correct analyses with
adequate discussion
Correct analyses with
comprehensive
discussion
5
0.4
2
SK3
Appraisal of the suitable and
efficient solutions.
Solve the question with correct
answers and discussions
SP4
P4
Incorrect answers
and discussion
Correctanswers
with minimal
discussion
Correct answers with
some discussion
Correct answers with
adequate discussion
Correct answers with
comprehensive
discussion
5
0.4
2
SK1
Selection of suitable analytical
techniques.
Adapt to the correct used of
equipment and measurement
technique
Incorrect equipment
and measurement
technique used
Correct equipment
used but minimal
measurement
technique shown
Correct equipment
used with average
measurement
technique shown
Correct equipment
used with adequate
measurement
technique shown
Correct equipment
used with well-versed
measurement
technique shown
5
0.6
3
Incorrect procedure
shown with lack of
understanding
Correct procedure
shown but minimal
understanding
Correct procedure
shown with average
understanding
Correct procedure
shown with adequate
understanding
Correct procedure
shown with
enthusiasam and wellversed understanding
5
0.6
3
Adapt appropriate method and
solutions relate to the labwork
Labwork (pratical)
SK3
Well-versed with the correct and
safe operational procedures
SP3
Adapt to the correct procedure
P5
Total(%)
3
20.0
TABLE OF CONTENT
CONTENT
PAGE
1.0 Objective
2.0 Learning Outcomes
3.0 Theory
5-7
4.0 Equipment
8-9
5.0 Procedure
10-13
6.0 Result and Calculation
14-19
7.0 Discussion
20-26
8.0 Conclusion
27
9.0 Reference
28
4
1.0 OBJECTIVE
1.
To To study the trajectory of a water jet issuing from an orifice.
2.
To determine the flow characteristics through a small orifice.
3.
To calculate the coefficient of discharge (CdC dCd) of the orifice.
4.
To compare theoretical and actual discharges.
2.
0 LEARNING OUTCOMES
At the end of the course, students should be able to apply the knowledge and skills they have learned
to:
1.
Understand the characteristics of different orifices.
2.
Understand the concept of contraction of the stream and energy loss.
3.
Understand the factors which influence the flow through orifice.
3. 0 THEORY
An orifice is an opening, of any size or shape, in a pipe or at the bottom or side wall of a container
(water tank, reservoir, etc.), through which fluid is discharged. If the geometric properties of the orifice
and the inherent properties of the fluid are known, the orifice can be used to measure flow rates. Flow
measurement by an orifice is based on the application of Bernoulli’s equation, which states that a
relationship exists between the pressure of the fluid and its velocity. The flow velocity and discharge
calculated based on the Bernoulli’s equation should be corrected to include the effects of energy loss
and viscosity. Therefore, for accurate results, the coefficient of velocity (Cv) and the coefficient of
discharge (Cd) should be calculated for an orifice. This experiment is being conducted to calibrate the
coefficients of the given orifices in the lab.
Bernoulli's Theorem applied between the water surface and orifice yields the theoretical velocity:
Vth  2gh
Where:
Vth = theoretical velocity
g = 9.81 m/s
5
h = head of water above the orifice centre
Theoretical Discharge: Qth  A 2gh Where is the area of the orifice.
Actual Discharge: Qact 
v
Where V is the volume of water collected and t is the time.
t
Coefficient of Discharge (Cd): Cd 
Qact
Qth
Cd accounts for energy losses due to viscosity, friction, and contraction.
Flow Through Orifices and Nozzles
Drawing (a) shows fluid streaming through a smoothly contracting nozzle, making a parallel jet. The
overall increase in speed through the contraction reduces non uniformity in the approaching flow, so
the fluid velocity should be uniform across the emerging jet. The cross-sectional area of the jet is the
same as that of the nozzle, so the flow rate is the product of the jet velocity and the nozzle area. In
drawings (b) and (c) however, the fluid does not emerge as a convergent stream, so the cross-sectional
area of the jet reduces to a contracted section or ‘vena contracta’. Over this section the streamlines are
parallel and velocity is effectively uniform. The flow rate is the product of the jet velocity and area of
the contracted section.
Figure 3.1: Examples of jet flows from nozzles and orifices
Jet Trajectory:

Water issuing horizontally from an orifice under pressure forms a parabolic trajectory.

The horizontal range x and vertical drop y relate to velocity v and height h by:
v  2 gh
6

t

Time of flight t is:
2y
g
Horizontal distance x :
x  vt  v
2y
g
Flow Through an Orifice:

Theoretical discharge:
Qtheoretical  A 2gH

Actual discharge Qactual measured by collecting volume over time.

Coefficient of discharge:
Qd 
Qactual
Qtheoretical
7
4.0 EQUIPMENT
EQUIPMENT
PICTURES
Orifice apparatus with hydraulic bench
Stop watch
8
Orifice 1 : Length 15mm, with 60°
contraction and 60° diverging
section
Orifice
Vernier Clipper
9
5.0 PROCEDURE
1. The water was filled into the three sump tanks to 3/4 height.
Figure 5.1: Filling Water into the Sump Tank
2. All the valves were opened before starting the experiment.
3. The main switch on the control box was switched on.
Figure 5.2: Switching on the Control Box
4. The water supply hose was connected to the Flow Through Orifice Tank inlet port.
5. It was ensured that the overflow port was connected with a hose and the hose was placed in the
volumetric tank.
10
6. The orifice plate to be tested was placed at the base of the apparatus tank.
7. The pump was switched on and water was allowed to flow into the orifice tank.
Figure 5.5: Adjusting Flow and Overflow
8. The flow was adjusted and allowed to pass over the overflow pipe.
9. The Pitot tube was adjusted and placed at the center of the outlet flow from the orifice plate.
10. Water was allowed to flow for around 3 to 4 minutes. It was ensured that no bubbles were present in
the manometer tubing.
Figure 5.6: Positioning the Pitot Tube
11. The water level of the tank height was recorded as Ho.
11
Figuire 5.5 : Recording tank levels Ho
12. The water level of the Pitot tube was recorded as Hc.
Figure 5.6 : Recording pilot tube lebel Hc
13. The diameter of the existing water jet (dc) was measured using the provided caliper.
Figure 5.8: Measuring Water Jet Diameter
12
14. All the recorded data was filled into the table below.
15. The experiment was repeated with different flow rates.
16. The experiment was also conducted with different orifice plates.
13
6.0 RESULTS, CALCULATION AND DATA COLLECTION
CALCULATION
14
15
16
RESULT
ORIFICE 1
Volu
me
(liters
)
Tim
e
(sec
)
Tank
Heig
ht,
𝐻𝑜
(mm)
Pitot
Tube
Heig
ht,
𝐻𝑐
(mm)
Orifice
Diamet
er,
𝐷𝑜
(mm)
Existin
g Water
Diamet
er,
𝐷𝑐
(mm)
10
46.2
4
40.7
6
23.9
2
110
116
29.7
14.0
Experim Theoreti Coeffici
ent
cal
ent of
Flowrate Flowrate Velocity,
,
,
𝐶𝑣
𝑄𝑒𝑥𝑝
𝑄𝑡ℎ𝑒𝑜
(𝑚3 /𝑠)
(𝑚3 /𝑠)
(𝑥10−4 ) (𝑥10−4 )
2.163
2.351
1.027
154
156
29.7
14.2
2.453
2.635
230
230
29.7
14.8
4.181
2.825
10
10
17
Coefficie
nt of
Contracti
on,
𝐶𝑐
Discharg
e
Coefficie
nt,
𝐶𝑑
0.896
0.920
1.006
0.925
0.931
1.000
1.480
1.480
ORIFICE 2
Volu
me
(liters
)
Tim
e
(se
c)
Tank
Heig
ht,
𝐻𝑜
(mm)
Pitot
Tube
Heig
ht,
𝐻𝑐
(mm)
Orifice
Diame
ter,
𝐷𝑜
(mm)
10
46.
59
41.
00
19.
01
160
162
201
231
10
10
Experim
ent
Flowrat
e,
𝑄𝑒𝑥𝑝
(𝑚3 /𝑠)
(𝑥10−4 )
2.146
Theoret
ical
Flowrat
e,
𝑄𝑡ℎ𝑒𝑜
(𝑚3 /𝑠)
(𝑥10−4 )
2.351
Coeffici
ent of
Velocity
,
𝐶𝑣
Coefficie
nt of
Contract
ion,
𝐶𝑐
Dischar
ge
Coeffici
ent,
𝐶𝑑
30.0
Existin
g
Water
Diame
ter,
𝐷𝑐
(mm)
11.3
1.006
0.908
0.913
210
30.0
12.0
2.439
2.635
1.022
0.906
0.926
231
30.0
12.4
5.260
2.825
1.024
1.818
1.862
Calculation Example:
1. Experimental Flowrate, 𝑄𝑒𝑥𝑝 =
Volume= 10ℓ x
𝑉𝑜𝑙𝑢𝑚𝑒,𝑚 3
𝑇𝑖𝑚𝑒,𝑠
0.001𝑚 3
1ℓ
Volume= 0.01𝑚3
0.01𝑚 3
𝑄𝑒𝑥𝑝 = 46.24𝑠
𝑄𝑒𝑥𝑝 =2.163𝑥10−4
𝐴
2. Theoretical Flowrate,𝑄𝑡ℎ𝑒𝑜 = 𝑜√2𝑔ℎ
𝜋(13𝑥10−3 )2
𝐴𝑜 =
4
𝐴𝑜 = 1.327𝑥10−4 𝑚2
𝑄𝑡ℎ𝑒𝑜= 1.327𝑥10
−4𝑚2
√(2)(9.81)(0.11)
𝑄𝑡ℎ𝑒𝑜= 1.949𝑥10−4 𝑚3 /𝑠
18
𝐻
3. Coefficient of Velocity, 𝐶𝑣 =√𝐻𝑐
𝑜
116
𝐶𝑣 =√110
𝐶𝑣 =√1.055
5. Coefficient of Contraction,𝐶𝑐 𝐶𝑣 =1.006
𝑄
4. Discharge Coefficient,𝐶𝑑 = 𝑄 𝑒𝑥𝑝
𝑡ℎ𝑒𝑜
2.163𝑥10−4
𝐶𝑑 =2.351𝑥10−4
𝐶𝑑 =0.920
𝐶
= 𝐶𝑑
𝑣
0.920
𝐶𝑐 =1.027
𝐶𝑐 =0.896
19
7.0 DISCUSSION
1.
Compare the calculated result between theoretical flow rate and the experimental flow rate
In the experiment conducted using the hydraulic bench a clear comparison was made between
theoretical and experimental flow rates for different tank heights and orifice configurations. For
example, in one trial using Orifice 1 with a tank height of 110 mm the experimental flow rate was 2.163
L/min while the theoretical flow rate was 2.351 L/min. Similarly for a tank height of 154 mm the
experimental flow rate was 2.453 L/min compared to a theoretical rate of 2.635 L/min. These results
consistently show that the experimental discharge is lower than the theoretical prediction. The deviation
can be attributed to real-world losses such as fluid viscosity, frictional resistance at the orifice edges,
turbulence during flow and imperfect stream contraction. These effects are not accounted for in
Bernoulli’s idealized assumptions which explains why the experimental values tend to fall short of the
calculated theoretical flow. This comparison not only confirms the necessity of correction factors such
as the discharge coefficient (Cd) but also highlights the practical importance of considering energy
losses in real engineering applications.
2. Calculate the Coefficient of Velocity, Cv, Coefficient of Contraction, Cc, and Discharge
Coefficient, Cd
20
.
21
22
23
24
25
26
8.0 CONCLUSION
The experiment was performed to examine water flow through different orifices by finding the
coefficients of velocity (CV), contraction (Cc), and discharge (Cd). Relevant measurements taken in the
experiment included the flow rate of water, height of the tank, and the diameter of the jet. The values of
these coefficients were determined and shown to be dependent on the type of orifice and experimental
conditions being considered.
Unlike the ideal values of discharge coefficient, the experimental discharge coefficient is a bit
different. This is because some of the energy in the fluids is usually lost due to viscosity, turbulence,
minor imperfections of the orifice, which are not considered in the theory. It is very important to consider
these vital factors of conditions in fluid.
Moreover, the study disclosed that the nature of the orifice matters quite much as it influences the
flow of the liquid. Varying the orifice geometry also influences jet contraction, flow rate, and hence the
total discharge of the liquid, necessitating the need for care when designing a liquid flow system.
27
REFERENCE
AE547-EN. (n.d.). Lab 9: Experimental Aerodynamics – Flow Visualization. Middle East Technical
University. Retrieved May 28, 2025, from http://www.ae.metu.edu.tr/~ae547/lab13/Lab9_manual.pdf
TecQuipment
Ltd.
(2022).
H4
Flow
Through
an
Orifice
datasheet.
https://www.tecquipment.com/assets/documents/datasheets/H4-Flow-Through-Orifice-Datasheet.pdf
Hilado, C. (2020). Flow through an orifice: Experiment No. 05. School of Civil, Environmental, and
Geological
Engineering,
Mechanics
of
https://www.scribd.com/document/470984231/Experiment-5
28
Fluids
Laboratory
Report.