Table of Contents

Summary………………………………………………………………………………….…2

Objective……………………………………………………………………………….…….2

Data, Observations and Results……………………………………………………………2

Discussions…………………………………………………………………………………..4

Conclusion……………….………………………………………………………………….6

References………………………………………………………………..…………………6

Appendices

1

Summary

The name of the equipment used for this experiment is TecQuipment Reynolds Number and

Transitional Flow Apparatus, H215/215A TecQuiment Hydraulic Bench, H1. This equipment

is used to see the pattern of the water flow rate. This equipment can help us to find pattern of

flow rate and also can help us to calculate the flow rate of the water. It is important to study

how to use the Reynolds number to calculate the flow pattern and also the Reynolds numbers

can be used to calculate other properties such as density, velocity, diameter and viscosity. We

must understand that Reynolds number is a ratio of inertia to viscous effect of a flow. The

experiment was conducted in UNITEN lab with my lab mates and was supervised by my lab

instructor Mr. Ibrahim. The procedure and rules which has been taught by Mr. Ibrahim were

strictly followed. We handle the equipment with care to avoid any damage. Before opening

the pipe flow we checked all the safety precaution and the experiment is done one by one by

my group members and me.

Objective

To investigate the relationship of flow condition and fluid velocity.

Data, Observations and Results

Table 1

Sample calculation

Flow rate, Q =volume (mᵌ)time(s)

= 0.001259

=0.00000385 mᵌ/s

2

The area is A=π d ²4

= 3.14159×(0.012) ²

4

=1.13×10^ (-4) m²

(B) Graph 1: kinematics viscosity graph

With the above graph the kinematics viscosity is = 0.9×10^ (-6) m²/s

The equation use to find Re number is from equation 5 which is:

ℜ=udV

…………. (5)

=0.135(0.012)0.9×10(−6)

=1797.34(transition flow)

3

0 500 1000 1500 2000 2500 3000 3500 40000

0.000005

0.00001

0.000015

0.00002

0.000025

0.00003

Flow rate versus Reynolds Number

first readingsecond reading

Re

flow

rate

,Q

(B) Graph 2: flow rate versus Re

Discussion

4

There are 3 types of flow condition. Laminar, transition and turbulent. Laminar flow, a

streak line is created when dye is injected in the flow. The line remains as a well-defined line

as it flows along, with only slight blurring due to molecular diffusion of the dye into the

surrounding water. For transition flow, the dye streak fluctuates in time and space, and

intermittent burst or irregular behaviour appears along the streak. For turbulent flow the dye

streak almost immediately becomes blurred and spreads across the entire pipe in a random

fashion.

Reynolds number is the ration of the inertia to viscous effect of a flow. The Reynolds

number for laminar flow is <2000 whereas for transition flow 2000 < Re <2500. For

turbulent flow is Reynolds number is > 2500. Based on our result that we got conducting the

experiment, we did the experiment two times to get accurate result. For the first time, the

laminar Re number that we got was 453.34, transition Re was 1797.34 and turbulent flow was

2933.34, Laminar and turbulent flow have achieve the theoretical value ,but our transition

didn’t achieve the theoretical value due to some parallax errors . Net we conduct again our

experiment and we got three different reading. First laminar Re was 698.66, transition Re was

2106.66 and turbulent Re was 3493.44. The second reading was perfect and all three reading

achieve the theoretical value.

In the graph it shows that the second reading is higher than the first reading. For laminar flow

the first reading we got was 453.34 but for the same laminar reading we got 698.66 for the

second reading. Transition value for first reading according to graph 1 is 1797.34 whereas for

second reading is 2106.66. For turbulent flow the first reading from graph is 2933.34,

whereas for second reading is 3493.44.

The experiment should be set up perfectly to get accurate data. The flow must be constant

and should not be high for the first time. The water flow in must be equal with the flow going

out through discharge pipe. Time is an important factor because it is used to calculate flow

rate of water. The time should be measured accurately because minor error in time will affect

the flow rate calculation. The most important precautions are our observation must be correct

when looking at the dye. We have to identify the flow correctly to avoid major error on

classifying the flow pattern.

5

Conclusion

In this experiment the main objectives was to investigate the relationship of flow condition

and fluids velocity. If the velocity increases the flow the Reynolds number increases. If we

look at the equation Reynolds number is ℜ= ρudμ

which says that the Re is directly

proportion with the density, velocity and diameter of the pipe. If the viscosity of the fluids

increases than Reynolds number will decrease. So in this experiment we tested upon the flow

pattern and velocity. We found that when the flow is low the dye show us a straight line

which we conclude it as a laminar flow. Whereas when the flow is fasten the dye

immediately goes away from view which we conclude it to be turbulent flow. What we learn

from this is that there is another flow called transition flow which is in between laminar and

turbulent flow. The flow is in medium speed and we can see the changes of the dye, it was I

straight line but the line was not long like laminar flow it started to blur. In conclusion we

know that when the velocity increase the flow is called turbulent and when the velocity is

decrease the condition of the water becomes laminar flow. If the flow is in medium speed the

flow is known to be transition flow.

References

MUHAMAD IBRAHIM BIN MAHMOD 2012, MEHB221 THERMOFLUIDS LAB

MANUAL

BRUCE R.MUNSON 2010, FUNDAMENTAL OF FLUIDS MECHANICS. 6th Ed. John

Wiley & Sons

Appendices

6