Performance investigation and blade analysis of a small horizontal axis wind turbine utilizing whale...

Mindanao University of Science and Technology

College of Engineering and Architecture

Lapasan, Cagayan de Oro City

In Partial Fulfillment of the Requirements

In

ME Project Study II

“PERFORMANCE INVESTIGATION AND BLADE ANALYSIS OF A

SMALL HORIZONTAL AXIS WIND TURBINE UTILIZING WHALE-

INSPIRED BLADE”

Presented by:

Petronillo D. Peligro

BS Mechanical Engineering – 5

Presented to:

Dr. Jonathan C. Maglasang

Adviser, ME Project Study II

March 2016

ii

APPROVAL SHEET

In Partial Fulfillment of the Requirements for the degree of Bachelor of

Science in Mechanical Engineering, this project study entitled “Performance

Investigation and blade analysis of a small horizontal axis wind turbine utilizing

whale- inspired blade”, has been prepared and submitted by Petronillo D. Peligro is

hereby recommended for examination by the panel of assessors.

DR. JONATHAN C. MAGLASANG

Adviser

Approved in Partial Fulfillment of the requirements for the degree of Bachelor

of Science in Mechanical Engineering by the Examination Panel.

ENGR. CELIL MAY R. YLAGAN DR. LEONEL L. PABILONA

Panel Member Panel Member

ENGR. EDWARD PETER F. ROLLO ENGR. ADONIS A. CLOSAS

Panel Member Panel Member

Accepted in Partial Fulfillment of the requirements for the degree of Bachelor

of Science in Mechanical Engineering.

March 2016

ATTY. DIONEL O. ALBINA

Dean, College of Engineering and Architecture

iii

Acknowledgement

First of all we thank god for finishing our thesis project successfully, and for

giving us strength to continue our thesis project even though we encounter many

problems during the actual building of our wind turbine.

We also thank our adviser Dr. Jonathan C. Maglasang for helping us about the

simulation parameters.

We thank all our classmates who helped us during our data gathering and for

their moral supports and sharing of ideas.

I thank my parents, and my sponsor for their financial and moral support.

iv

Abstract

The study introduces a new blade geometry that was inspired by a hump back

whale flippers. This blade was introduced first by Dr. Frank Fish and named “whale-

inspired blade”.

Using solidworks and qblade softwares we simulate the blade geometry and

the wind turbine rotor. Whale- inspired blade shows that it increased its Cl/Cd more

than the unbumped blade’s Cl/Cd when the velocity is increasing and also when the

angle of attack is increasing. During the flow simulation the unbumped blade’s flow

lines already separates at 15o angle of attack, as the angle of attack increases the flow

separation also increases that will cause stall and we don’t want that to happen, but

the whale- inspired blade’s flow simulation result was different as it creates swirling

vortices that re- energized the boundary layer to re attach the flow lines, that’s why

whale- inspired blade have more Cl/Cd compared to the unbumped blade when the

angle of attack is increasing.

We compare our Cl/Cd results to the previous year’s corrugated dragonfly-

wing blade and we can tell that our whale- inspired blade is much better than their

corrugated dragonfly- wing blade.

v

List of Abbreviations

P= Power

𝞺= density

Cm= Average chord length

AR= Aspect ratio

AT= Planform area

Rm= mean radius

Rt= tip radius

Rb= hub radius

Zb= Blade number

Cd= Drag coefficient

CL= Lift coefficient

Fd= Drag force

FL= Lift Force

V∞= Undisturbed wind

v= Kinematic viscosity

µ= Dynamic viscosity

b= blade length

TABLE OF CONTENTS Approval Sheet ii

Acknowledgement iii

Abstract iv

List of Abbreviations v

CHAPTER 1: INTRODUCTION 1.1 Background of the Study 1

1.1.1 Wind Turbine 1

1.1.2 Horizontal Axis Wind Turbine 1

1.1.3 Wind Turbine Blade 1

1.1.4 Humpback Whale Flippers 1

1.2 Statement of the Problem 2

1.3 Objectives 2

1.3.1 Main Objective 2

1.3.2 Specific Objective 2

1.4 Significance of the Study 2

1.5 Scope and Limitations 2

1.6 Theoretical Framework 2

1.6.1 Power that can be Extracted from Wind 2

1.6.2 Reynolds Number 3

1.6.3 Planform Area 3

1.6.4 Aspect Ratio 3

1.6.5 Solidity 3

1.6.6 Lift and Drag Coefficient 3

1.6.7 Force and Velocity Triangle 4

1.6.8 Blade Element Momentum 4

1.6.9 Mach number 4

CHAPTER 2: REVIEW OF RELATED LITERATURE

2.1 Studies on Humpback Whale Flippers 5

2.2 Studies on Whale- inspired blade 6

CHAPTER 3: METHODOLOGY

3.1 Design Requirement 7

3.2 Conceptual Design 7

3.2.1 Flow Simulation of Every Bumps 7

3.3 Preliminary Design 10

3.3.1 Flow Simulation at 8 m/s 10

3.3.2 Blade Calculation 13

3.3.3 Rotor Simulation 14

3.3.4 Calculation of Rotor Specification 15

3.4 Detailed Design 15

3.4.1 Blade and Rotor Specification 15

3.5 Gathering of Materials 16

3.6 Construction 16

3.7 Testing 17

3.7.1 Experimental Set-up Flow Chart 17

3.8 Data Analysis 17

3.9 Thesis Presentation 17

CHAPTER 4: RESULTS AND DISCUSSION

4.1 Graphs of by Bump Blade Simulation 18

4.1.1 1.5 m/s Graphs of Each Bump 18

4.1.2 1.5 m/s Blade Graph Comparison of Each Bump 22

4.1.3 8 m/s Graphs of Each Bump 22

4.1.4 8 m/s Blade Graph Comparison of Each Bump 26

4.1.5 Discussion 27

4.2 Graph of the Final Blade Simulation at Different Wind Speed 27

4.2.1 1 m/s Graph 27

4.2.2 2 m/s Graph 28

4.2.3 4 m/s Graph 28

4.2.4 8 m/s Graph 29

4.2.5 16 m/s Graph 29

4.2.6 Graph Comparison of Each Wind Speeds 30

4.2.7 Discussion 30

4.3 Theoretical and Actual 30

4.3.1 Theoretical 30

4.3.2 Actual 31

4.3.3 Theoretical vs. Actual 31

4.3.4 Discussion 32

4.4 Previous year’s Corrugated Dragonfly- wing Blade 32

Vs. This year’s Whale- inspired Blade

4.4.1 Discussion 36

4.5 Graphs of the Rotor Simulation Datas 36

4.5.1 Discussion 36

4.6 Actual Rotor Graph 37

4.6.1 Discussion 37

CHAPTER 5: CONCLUSION AND RECOMMENDATION

5.1 Conclusion 38

5.2 Recommendation 38

REFERENCES 39

APPENDIX

Appendix A: Tables 40

Appendix B: Pictures 42

Performance Investigation and Blade Analysis of a Small Horizontal Axis Wind

Turbine Utilizing Whale- Inspired Blade

1

CHAPTER 1

INTRODUCTION

1.1 Background of the study

1.1.1 Wind Turbine

Wind turbine is a device that converts kinetic energy from the wind into

electrical power. The term appears to have migrated from parallel hydroelectric

technology (rotary propeller).

1.1.2 Horizontal Axis Wind Turbine

Horizontal-axis wind turbines (HAWT) have the main rotor shaft and

electrical generator at the top of a tower, and may be pointed into or out of the wind.

Small turbines are pointed by a simple wind vane, while large turbines generally use a

wind sensor coupled with a servo motor. Most have a gearbox, which turns the slow

rotation of the blades into a quicker rotation that is more suitable to drive an electrical

generator.

1.1.3 Wind Turbine Blade

Wind turbine blades are shaped to generate the maximum power from the

wind. The blade plays a big role in a wind turbine as it increases or decreases the

efficiency of the turbine, that’s why we come up with a new blade geometry that was

invented by Doctor Frank Fish the whale- inspired blade.

1.1.4 Humpback Whale Flippers

“The humpback whale (Megaptera novaeangliae) is reported to use its

elongate pectoral flippers during swimming maneuvers. The morphology of the

flipper from a 9.02m whale was evaluated with regard to this hydrodynamic function.

The flipper had a wing- like, high aspect ratio plan form. Rounded tubercles were

regularly interspersed along the flippers leading edge. The flipper was cut into 71 2.5

cm cross sections and photographed. Except for sections near the distal tip, flipper

sections were symmetrical with no camber. Flipper sections had a blunt, rounded

leading edge and a highly tapered trailing edge. The humpback whale flipper had a

cross-sectional design typical of manufactured aerodynamic foils for lift generation.

The morphology and placement of leading edge tubercles suggest that they function

as enhanced lift devices to control flow over the flipper and maintain lift at high angle

of attack. The morphology of the humpback whale flipper suggests that it is adapted

for high maneuverability associated with the whale’s unique feeding behavior.” (Fish

and Battle 1995:51)

According to Doctor Frank Fish humpback whale flipper was observed that it

decreased drag by 32%, increased lift by 8%, and increased angle of attack by 40%

over an unbumped flipper.



2

1.2 Statement of the Problem

We all know that some rural areas have no electricity. Many families in a rural

area that have no electricity are using a lamp and a candle to light their home, but

there is a danger in using lamp and candle, because it can be the cause to burn their

houses, and we don’t want that to happen. Many families also cannot afford to pay

electric bills. In Siquijor where my grandfather lives, there was no electricity there,

and even if there is electricity he still can’t afford to pay the bills as he said. It is not

good to see families that have no electricity, as students cannot study well, and they

can only do limited work. Using wind turbine it can help those families to provide

their need of electricity.

1.3 Objectives

1.3.1 Main Objectives

To design, build, and test a small horizontal axis wind turbine utilizing whale-

inspired blade

1.3.2 Specific Objective

To determine the performance using scientific calculation and experimental

method

1.4 Significance of the Study

It helps the families in the rural areas who have no electricity to have their

own electricity that will light their home.

It will show a new design of a wind turbine blade.

1.5 Scope and Limitations

The research focus on studying the performance of a whale- inspired blade and

what will be the effect when it will serve as a rotor of a small horizontal axis wind

turbine. Our thesis project will be put on the LRC building, where our actual data

gathering will be performed.

1.6 Theoretical Framework

1.6.1 Power that can be extracted from wind

Betz's law calculates the maximum power that can be extracted from the wind,

independent of the design of a wind turbine in open flow. It was published in 1919, by

the German physicist Albert Betz. The law is derived from the principles of

conservation of mass and momentum of the air stream flowing through an idealized

"actuator disk" that extracts energy from the wind stream. According to Betz's law, no

turbine can capture more than 16/27 (59.3%) of the kinetic energy in wind. The factor



3

16/27 (0.593) is known as Betz's coefficient. Practical utility-scale wind turbines

achieve at peak 75% to 80% of the Betz limit.

P=

A

3(

)

1.6.2 Reynolds Number

Reynolds number is a dimensionless quantity that is used to help predict

similar flow patterns in different fluid flow situations.

v=

Re= CmV/v

1.6.3 Planform Area

The planform area of a wing is the area of a wing as if it were projected down

onto the ground below it.

AT= Cm X b

1.6.4 Aspect Ratio

Aspect Ratio is the ratio of its sizes in different dimensions. Blade’s

aspect ratio is equal to its span over the average chord length.

Cm= CN +…+ CN+1

AR= b/Cm

1.6.5 Blade Solidity

rm= √

Pitch=

Blade solidity = Cm/Pitch

1.6.6 Lift and Drag Coefficient

The lift coefficient (CL) is a dimensionless coefficient that relates the lift

generated by a lifting body to the fluid density around the body, the fluid velocity and

an associated reference area. A lifting body is a foil or a complete foil-bearing body

such as a fixed-wing aircraft. CL is a function of the angle of the body to the flow, its

Reynolds number and it’s Mach number. The lift coefficient cl refers to the dynamic

lift characteristics of a two-dimensional foil section, with the reference area replaced

by the foil chord.

CL=



4

The drag coefficient (Cd) is a dimensionless quantity that is used to quantify

the drag or resistance of an object in a fluid environment, such as air or water. It is

used in the drag equation, where a lower drag coefficient indicates the object will

have less aerodynamic or hydrodynamic drag. The drag coefficient is always

associated with a particular surface area.

The drag coefficient of any object comprises the effects of the two basic contributors

to fluid dynamic drag: skin friction and form drag. The drag coefficient of a lifting

airfoil or hydrofoil also includes the effects of lift-induced drag. The drag coefficient

of a complete structure such as an aircraft also includes the effects of interference

drag.

Cd=

1.6.7 Force and Velocity Triangle

1.6.8 Blade Element Momentum

Blade element momentum theory is a theory that combines both blade element

theory and momentum theory. It is used to calculate the local forces on a wind-turbine

blade. Blade element theory is combined with momentum theory to alleviate some of

the difficulties in calculating the induced velocities at the rotor.

1.6.9 Mach Number

Mach number is equal to the speed of the object over the speed of sound. Our

wind turbine operates at subsonic.

Mach number= ω/ speed of sound



5

CHAPTER 2

REVIEW OF RELATED LITERATURE

2.1 Studies on Humpback Whale Flippers

“The advantage of the humpback-whale flipper seems to be the angle of attack

it’s capable of–the angle between the flow of water and the face of the flipper. When

the angle of attack of a whale flipper–or an airplane wing–becomes too steep, the

result is something called stall. In aviation, stall means that there isn’t enough air

flowing over the top surface of the wing. This causes a combination of increased drag

and lost lift, a potentially dangerous situation that can result in a sudden loss of

altitude. Previous experiments have shown; however, that the angle of attack of a

humpback-whale flipper can be up to 40 percent steeper than that of a smooth flipper

before stall occurs. The Harvard research validates the first controlled wind-tunnel

tests of model flippers, conducted five years ago at the U.S. Naval Academy, in

Annapolis, MD, where it was shown that stall typically occurring at a 12-degree angle

of attack is delayed until the angle reaches 18 degrees. In these tests, drag was

reduced by 32 percent and lift improved by 8 percent.” (Tyler Hamilton)

“Wind tunnel test of scale model humpback whale flippers have revealed that

the scalloped, bumpy flipper is a more efficient wing design than is currently use by

aeronautics industry on airplanes. The tests show that bump-ridged flippers do not

stall as quickly and produce more lift and less drag than comparably sized sleek

flippers. The sleek flipper performance was similar to a typical airplane wing. But the

tubercle flipper exhibited nearly 8 percent better lift properties, and withstood stall at

a 40 percent steeper wind angle. The team was particularly surprised to discover that

the flipper with tubercles produced as much as 32 percent lower drag than the sleek

flipper. This new understanding of humpback whale flipper aerodynamics has

implications for airplane wing and underwater vehicle design. Increased lift (the

upward force on an airplane wing) at higher wind angles affects how easily airplanes

take off, and helps pilots slow down during landing. Improved resistance to stall

would add a new margin of safety to aircraft flight and also make planes more

maneuverable. Drag the rearward force on an airplane wing affects how much fuel the

airplane must consume during flight. Stall occurs when the air no longer flows

smoothly over the top of the wing but separates from the top of the wing before

reaching the trailing edge. When an airplane wing stalls, it dramatically loses lift

while incurring an increase in drag. As whales move through the water, the tubercles

disrupt the line of pressure against the leading edge of the flippers. The row of

tubercles sheer the flow of water and redirect it into the scalloped valley between each

tubercle, causing swirling vortices that roll up and over the flipper to actually enhance

lift properties. Humpback whales maneuver in the water with surprising agility for 44-

foot animals, particularly when they are hunting for food. By exhaling air underwater

as they turn in a circle, the whales create a cylindrical wall of bubbles that herd small

fish inside. Then they barrel up through the middle of the “bubble net,” mouth open

wide, to scoop up their prey.” (Frank Fish, Lauren Howle, David Miklosovic and

Mark Murray)



6

“But after years of study, starting with a whale that washed up on a New

Jersey beach, Frank Fish thinks he knows their secret. The bumps cause water to flow

over the flippers more smoothly, giving the giant mammal the ability to swim tight

circles around its prey. What works in the ocean seems to work in air. Already a

flipper like prototype is generating energy on Canada's Prince Edward Island, with

twin, bumpy-edged blades knifing through the air. And this summer, an industrial fan

company plans to roll out its own whale-inspired model - moving the same amount of

air with half the usual number of blades and thus a smaller, energy-saving motor.

Some scientists were skeptical at first, but the concept now has gotten support from

independent researchers, most recently some Harvard engineers who wrote up their

findings in the respected journal Physical Review Letters. The first of these animal-

inspired ideas to reach fruition is the whale-flipper wind turbine. he scientific

literature had scant reference to the flipper bumps, called tubercles. Fish reasoned that

because the whale's flippers remained effective at a high angle, the mammal was

therefore able to maneuver in tight circles. In fact, this is how it traps its prey,

surrounding smaller fish in a "net" of bubbles that they are unwilling to cross. In

2004, along with engineers from the US Naval Academy and Duke University, Fish

published hard data: Whereas a smooth-edged flipper stalled at less than 12 degrees,

the bumpy, "scalloped" version did not stall until it was tilted more than 16 degrees -

an increase of nearly 40 percent.” (McClatchy newspapers)

2.2 Studies on Whale- Inspired Blade

“The objective of this project is thus to investigate improvement of HAWT

blade design by incorporating the bumps on humpback whales fins into blades. This

application is thought to produce more aerodynamic blades by creating turbulence in

the airflow behind each groove. This project focused on designing, simulating, and

analyzing a HAWT with whale-inspired blades to determine the differences in the

associated turbulent flow field, boundary layer attachment, and pressure gradients that

cause lift and drag compared to traditional HAWTs using computational studies. It is

shown that a whale-inspired blade offers the possibility of an improved design at

higher angles of attack. The blade is characterized by a superior lift/drag ratio due to

greater boundary layer attachment from vortices energizing the boundary layer.”

(Alex Krause and Raquel Robinson)



7

CHAPTER 3

METHODOLOGY

3.1 Design Requirement

The cut- in wind speed must be 1 m/s

The cut- out rpm of the rotor must be 2900 rpm

The blade must fit on the wind tunnel

3.2 Conceptual Design

Using Solidworks we simulate from 0- 7 numbers of bumps to see which of

them are the best to be put on our wind turbine rotor. We differentiate those numbers

of bumps at two wind speeds 1.5 m/s and 8 m/s. We choose 7 numbers of bumps,

because when the wind speed increases its Cl/Cd will become much better than the

other number of bumps although the unbumped blade is much better when the wind

speed is low. You can also see the graph comparison at chapter 4 results and

discussion. As you can see in the flow simulation pictures the flow lines on the

unbumped blade was already separating, while the flow lines on the 7 bump blade

was still attached. The airfoil we selected was NACA 2414, because it can operate at

low Reynolds number. The flow simulation can be seen below.

3.2.1 Flow Simulation of every bumps

Unbumped blade:



8

1 Bump blade:

2 Bump blade:

3 Bump blade:



9

4 Bump blade:

5 Bump blade:

6 Bump blade:



10

7 Bump blade:

3.3 Preliminary Design

We design a new blade geometry called a whale- inspired blade. We didn’t

taper the blade, because this is just a blade for a small horizontal axis wind turbine,

and the stress on the blade can be neglected for a small wind turbine rotor. This

bumpy blade was inspired by a humpback whale flipper. We based the choosing of

number of bumps to the solidworks simulation data.

3.3.1 Flow Simulation at 8 m/s

0o Angle of Attack:



11

5o Angle of Attack:

10

o Angle of Attack:

15

o Angle of Attack:



12

20o Angle of Attack:

25

o Angle of Attack:

30

o Angle of Attack:



13



3.3.2 Blade Calculation

Planform Area:

AT = Cm X b

AT = (0.089m) (0.28m) = 0.0251 m2

Blade Aspect Ratio:

AR= b/ Cm

AR= 280 mm/ 89mm = 3.146



14

3.3.3 Rotor Simulation



15

3.3.4 Calculation of Rotor Specification

Solidity:

rm= √

rm = √

rm = 0.247m

Pitch =

Pitch =

Pitch = 0.25866m

Solidity = 89mm/ 258.66mm

Solidity = 0.34

3.4 Detailed Design

3.4.1 Blade and Rotor Specification

Blade length = 280 mm

Average Chord Length= 89 mm

Hub Diameter= 127 mm

Aspect Ratio= 3.146

Planform Area= 0.0251 m2

Solidity= 0.34

Number of Blades= 3

Number of Bumps= 7

Rotor Diameter = 687mm

Blade Material: PLA Plastic



16

3.5 Gathering of Materials

Materials used to create the rotor:

Carbon Fiber Tube

PLA Plastic

3D Printed Hub

PVC Pipe

3 8mm Bearings

3.6 Construction

We will construct our wind turbine according to the datas and specifications

that we get in each specific study. The construction of the small horizontal axis wind

turbine will be held at the top of LRC building. We made our wind turbine detachable

so that we can just easily carry it when we finish gathering the data.



17

3.7 Testing

3.7.1 Experimental Set-up Flow Chart

We will put the whale- inspired blade in the wind tunnel, and see its CL/CD in

different angles of attack, after that we will use the whale- inspired blade as our wind

turbine rotor, and assemble the small horizontal axis wind turbine with a built in pitch

control. We will measure the wind speed in the area using the anemometer and we

will get the rotor rpm using the tachometer. Using the multi meter we will measure

the current and voltage of the generator and then we will use the formula P= IV to get

the power output of the generator. The Data that we gathered are all in the appendix.

3.8 Data Analysis

We analyzed the datas that we got, to see if it was correct. During the data

gathering we found some mistakes especially on the tachometer reading, because we

thought that the rpm reading of the tachometer was already the true rpm without

knowing that we still need to divide it to its blade number.

3.9 Thesis Presentation

We will present the datas, to the panels.

Wind Turbine

Wind Tunnel

Whale- Inspired

Blade

Multimeter

Generator

Anemometer and

Tachometer



18

CHAPTER 4

RESULTS AND DISCUSSION

4.1 Graphs of by Bump Blade Simulations

4.1.1 1.5 m/s Graphs of each bump

Unbumped blade Graph:

1 bump blade graph:



19

2 bump blade graph:

3 bump blade graph:



20

4 bump blade graph:

5 bump blade graph:



21

6 bump blade graph:

7 bump blade graph:



22

4.1.2 1.5 m/s Blade graph comparison of each bump

4.1.3 8 m/s Graphs of each bump

Unbumped blade graph:



23

1 bump blade graph:

2 bump blade graph:



24

3 bump blade graph:

4 bump blade graph:



25

5 bump blade graph:

6 bump blade graph:



26

7 bump blade graph:

4.1.4 8 m/s Blade Graph Comparison of Each Bump



27

4.1.5 Discussion

When we observed the graph comparison of each bump at 2 different wind

speeds the 7 bump exceeds all of them at 8 m/s wind speed at an angle of attack of

10o. Although the unbumped blade exceeds them all at 10

o angle of attack at 1.5 m/s

we still choose the 7 bump blade, because at higher angle of attack the 7 bump blade

has more Cl/Cd compare to the other choices.

4.2 Graph of the Final Blade Simulation at Different Wind Speeds

4.2.1 1 m/s Graph



28

4.2.2 2 m/s Graph

4.2.3 4 m/s Graph



29

4.2.4 8 m/s Graph

4.2.5 16 m/s Graph



30

4.2.6 Graph Comparison of Each Wind Speeds

4.2.7 Discussion

As we you can see on the graph comparison of each wind speeds, we can

conclude that the higher the wind speed the Cl/Cd will also become higher.

4.3 Theoretical and Actual

4.3.1 Theoretical



31

4.3.2 Actual

4.3.3 Theoretical vs. Actual



32

4.3.4 Discussion

The actual graph for Cl/Cd ends at 20 degrees angle of attack, because the

wind tunnel’s angle of attack is limited only at 20 degrees. We can see from the graph

that the actual wind tunnel data have much higher Cl/Cd than the theoretical at 10o

angle of attack. Although there are some differences in the actual data and the

theoretical data we can still see that it was just minimal.

4.4 Previous year’s Corrugated Dragonfly-wing Blade vs. This year’s Whale-

inspired blade

Note: The black graph is the previous year’s Corrugated Dragonfly- wing

blade and the white graph is this year’s whale- inspired blade



33



34



35



36

4.4.1 Discussion

When we compare the graphs we can see that our whale- inspired blade is

much better than the previous year’s corrugated dragonfly- wing blade. Although the

wind speeds are not the same we can still conclude that this year’s whale inspired

blade is much better, because it provides more Cl/Cd.

4.5 Graphs of the Rotor Simulation datas

4.5.1 Discussion

We can see that when the wind speed increases the power generation will also

increase.



37

4.6 Actual Rotor Graph

4.6.1 Discussion

During the actual data gathering we measure the wind speed using the digital

anemometer, and use the tachometer to measure the rpm of our wind turbine. We

perform 3 trials on each day, and we perform the data gathering on Monday and

Wednesday. We can see from the graph that when the wind speed increases the rpm

of the rotor also increases.



38

CHAPTER 5

CONCLUSION AND RECOMMENDATION

5.1 Conclusion

Whale- inspired blade increases its Cl/Cd when the wind speed increases.

Among the different number of bumps that I simulate I conclude that what I read in

different journals about this whale- inspired blade was true, it really create vortices to

re-energized the boundary layer and increase its Cl/Cd. Our whale- inspired blade is

also much better than the previous year’s corrugated dragonfly- wing blade as I

compare their graph to our graph.

5.2 Recommendation

I recommend to the next batch that will continue this study to have a

simulation time span of 1 year, and add at least 8 different wind speeds in their

simulations of every bump to clearly see what the best number of bumps. Make sure

that the wind tunnel is available as early as possible. Increase the number of bumps if

possible and observed what will be the changes.



39

REFERENCES

[1] Alex Krause and Raquel Robinson . Improving Wind Turbine Efficiency through

Whales-inspired Blade Design. October 2009

[2] Hugo T. C. Pedro and Marcelo H. Kobayashi. Numerical Study of stall delay on

humpback whale flippers. January 2008

[3] O. L. Hansen. Aerodynamics of Wind Turbines Second Edition. 2008

[4] Derrick Custodio. The Effect of Humpback Whale-like Leading Edge

Protuberances on Hydrofoil Performance. December 2007

[5] D. S. Miklosovic M. M. Murray L. E. Howle F. E. Fish. Leading-edge tubercles

delay stall on humpback whale Megaptera novaeangliae flippers. MAY 2004

[6] Damià Rita Espada. AERODYNAMIC ASSESSMENT OF HUMPBACK

WHALE VENTRAL FIN SHAPES. September 2011

[7] Mukund R. Patel, Ph.D., P.E. Wind and Solar Power Systems. 1999

[8] Jhonny T. Cabasag. Design Implementation and Analysis of Corrugated

Dragonfly-wing Blade and Brimmed-diffuser Shroud to a 300-watt Type Horizontal

Axis Wind Turbine Model. March 2015

[9] Wood, D., Small Wind Turbine: Analysis, Design and Application, 2011



40

APPENDIX

Appendix A: Tables

1. 1.5 m/s Cl/Cd Table of by Bump Simulation Data

Number

of

Bumps

10

degrees

15

degrees

20

degrees

25

degrees

30

degrees

35

degrees

0 3.65123 3.52174 2.49468 1.58234 1.38194 1.18326

1 2.98922 3.59928 1.91199 1.93083 1.64068 1.46615

2 3.27389 3.00962 2.75662 2.16615 1.67847 1.33706

3 3.69776 2.65195 2.80114 2.06474 1.52194 1.41748

4 3.90359 2.64957 2.67531 2.0553 1.58496 1.37262

5 3.69798 2.57833 2.65901 2.0723 1.63273 1.45417

6 3.51298 2.84031 2.65632 2.10789 1.66617 1.41269

7 3.53526 2.93375 2.69722 2.10797 1.67777 1.46454

2. 8 m/s Cl/Cd Table of by Bump Simulation Data

Number

of Bumps

10

degrees

15

degrees

20

degrees

25

degrees

30

degrees

35

degrees

0 4.5346 3.4398 2.69982 1.4769 1.2845 1.043

1 3.431 3.4216 2.16782 1.8567 1.643 1.4577

2 3.921 3.3215 2.86144 2.25321 1.69832 1.332

3 4.3315 2.98681 2.8512 2.10142 1.6372 1.385

4 4.98731 2.943 2.913 2.09836 1.677 1.413

5 4.4632 2.8236 2.896 2.10785 1.71 1.5

6 4.3213 3.143 2.7912 2.245134 1.73186 1.462

7 5.138 3.538 3.026748 2.247174 1.76 1.52

3. Final Blade Design Simulation Data, Cl/Cd Table

1 m/s 2 m/s 4 m/s 8 m/s 16 m/s

0 degrees 0.57288 -0.0215773 0.726073062 1.79544 1.9014

5 degrees 2.9475 3.851227 5.5977 6.158129 7.0853

10 degrees 3.239 3.72125 4.6597 5.1377 6.070415

15 degrees 2.6132357 3 3.3491 3.538 3.3864

20 degrees 2.58158 2.76 2.95085 3.02675 3.0852093

25 degrees 2.0375 2.152 2.210488 2.247174 2.28099215

30 degrees 1.64623 1.70234 1.734874 1.76 1.774916338

35 degrees 1.4431354 1.47652 1.499867 1.52007 1.533690411

40 degrees 1.125 1.14751 1.159957 1.168077 1.17492946



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4. Actual Cl/Cd Data From Wind Tunnel

AoA LIFT (N) DRAG (N)

Cl/Cd

0 1.254045 0.685065 1.830548926

2 1.42572 0.619665 2.300791557

4 1.476405 0.21909 6.73880597

6 1.60557 0.21255 7.553846154

8 1.764165 0.26487 6.660493827

10 1.836105 0.2943 6.238888889

12 2.05683 0.397305 5.176954733

14 2.21379 0.57552 3.846590909

16 2.49501 0.658905 3.786600496

18 2.66178 0.75537 3.523809524

20 2.88414 0.858375 3.36

5. Actual Rotor Data

Wind Speed RPM

Monday Trial 1 3.7 m/s 208.4667



Wednesday Trial 1 4.7m/s 261.5333

Wednesday Trial 2 4.1 m/s 244

Wednesday Trial 3 1.5 m/s 118.6667

Appendix B: Pictures

1. Wind Turbine Rotor and Blade



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2. Data Gathering at LRC

3. Wind Tunnel Testing



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4. Blade Painting

Performance investigation and blade analysis of a small horizontal axis wind turbine utilizing whale...

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