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Design and Development of a Multi-

Element Active Aerodynamic Package to

Enhance the Performance of Taylor’s

Formula SAE Car

Lee Wen Yew*, Abdulkareem Sh. Mahdi Al-Obaidi, Satesh Narayana Namasivayam

Department of Mechanical Engineering,

School of Engineering, Taylor’s University, Malaysia.

* wenyew.lee@gmail.com

Abstract

This study aims to provide an initial prediction on the effects of an aerodynamic

package in affecting the performance on Taylor’s Formula SAE race car. A downforce

of 90.830 N and drag of 186.018 N for the simplified Taylor’s Racing Team TR 16 race

car was identified through a 3D CFD simulation using the Reynold’s Averaged Navier-

Stokes k-, model at a velocity of 17.88 m/s. The lift-drag ratio of the car was calculated

and the corresponding lap time recorded for the four dynamic events in the Formula

SAE competition was taken as the benchmark. The lift-to-drag ratio of 0.488 for the

TR 16 race car indicated that the race car is aerodynamically efficient which contributes

to a slower lap time and higher fuel consumption. The diffuser was analyzed and a 3D

CFD simulation concluded that at an inlet angle of 3: and outlet angle of 22:, the highest

downforce of 253.628 N and drag of 49.651 N was recorded. The results were input to

the lap time simulator and it recorded the fastest lap time as compared to the other

configurations. The two element front wing with configuration of pitch of 13: for the

main element and pitch of 30: for the flap recorded the highest downforce of 131.165

N and drag of 37.504 N. The results were input to the lap time simulator and

configuration mentioned above recorded the fastest lap time. Both the diffuser and front

wing produced a downforce higher than the race car as well as a higher lift-to-drag ratio

of 5.108 and 3.497 respectively as compared to 0.488 for the TR 16 race car.

Consequently, by manipulating only the downforce and lift-to-drag ratio produced, the

lap time recorded by the diffuser and two-element front wing was faster than the car

with no aerodynamic package. This proves the initial prediction that adding an

aerodynamic package to the TR 16 race car will enhance its performance.

Keywords: FSAE Car, Multi-element front wing, Diffuser, Computational Fluid

Dynamics, Reynold’s Averaged Navier-Stokes k-, model

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1. Introduction

When vehicles travel at high speeds, the airflow passing along the geometry of

the car will generate lift and a nose-up pitching moment [1]. The lifting force reduces

the tyre contact patch of the vehicle, leading to lesser traction and lower lateral stability.

This can be countered by the introduction of an aerodynamic package that generates

negative lift or downforce. Katz [2] mentioned that race car designers only understood

the importance of vehicle aerodynamic by the late 1960s. This led to the advent of

incorporating aerodynamic packages to race cars and later shaped the future of the

motorsports scene.

In the context of Formula Society of Automotive Engineers (FSAE) races,

Wordley [3] conducted an initial prediction study and found that the incorporation of

an aerodynamic package improves the overall performance of the a race car. An

aerodynamic package consists of a diffuser, front wing or rear wing. The front wing

consists of endplates and an airfoil that acts as the element that produces the majority

of downforce as well as drag. Merkel [4] conducted a study to analyze the effects of a

multi-element wing specifically on the vehicle’s aerodynamic downforce. This study

determined that multi-element wings produced more significant downforce as

compared to a single element wing. Zhang [5] identified ground effect as a major factor

that increases downforce. It can be said that the diffuser which functions using a

difference in pressure as well as ground effect contributes the most significant

downforce in an aerodynamic package.

This paper aims to provide an initial prediction of the downforce and drag

produced by the Taylor’s Racing Team 2016 FSAE race car TR 16. Furthermore, this

paper aims to investigate if the addition of an aerodynamic package to the race car will

enhance its performance. First, the parameters of the TR 16 race car will be determined

and a 3D computational fluid dynamic (CFD) analysis will be conducted to analyze the

downforce as well as the lift-to-drag ratio7;

<, produced. A lap time simulator will be

used to identify the lap time the TR 16 race car records based on the four separate

dynamic events in the FSAE racing competition. An aerodynamic package, namely the

diffuser and front wing will be designed and a 3D CFD simulation will be conducted

as well. The inlet as well as the outlet angle of the diffuser will be manipulated and the

effects will be compared. A Selig S1223 airfoil is chosen to be the main airfoil to be

used in the design of the front wing. The pitch or angle of attack of the airfoil and its

corresponding effect on the downforce and drag produced will be analyzed. A two

element front wing will be designed based on the results obtained from the single

element front wing. The downforce and";

< obtained from the diffuser and front wing

will be input to the lap time simulator as well to determine which configuration yields

the best results in terms of lap time reductions. This also serves as an initial prediction

that by increasing the downforce produced as well as";

<, the lap time recorded for each

dynamic event will be reduced.

2. Research Methodology

2.1 3D Geometry Modelling

TR 16 was chosen for this study as a means of continuous improvement in the design

and performance of the car. The race car was designed in Solidworks and further

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simplified using surface modelling. Fig. 1 depicts the model of the car as well as the

simplified version taken for 3D CFD analysis. The vehicle was modelled with a height,

length, width and ground clearance of 1.45 m, 2.845 m, 1.375 m and 0.08m. Fig. 2

shows the model for the aerodynamic package that will be analyzed individually as well

as incorporated into TR 16 for analysis. The diffuser is designed with a dimension of

2.3 m in length and maximum height of 0.322 m with a thickness of 0.005 m. The front

wing endplate configuration is designed to be 0.5 m in length, front height of 0.1 m and

rear height of 0.2 m with a thickness of 0.005 m.

(a) (b)

Figure 1. (a) Model of TR 16 Race Car (b) Simplified model of TR 16 Race Car

(a) (b) (c)

Figure 2. (a) Proposed Diffuser Model (b) Single Element Front Wing (c) Two

Element Front Wing

2.2 Numerical Method

2.2.1 Model and Meshing Setup

An enclosed boundary domain was created to simulate the airflow along the

geometry of the car body as well as the aerodynamic package. The model is sliced in

half and assumed to be symmetric with a steady flow. An inlet, outlet, symmetry and

wall regions were created to emulate real life conditions as closely as possible. In efforts

to reduce the computational time, the dimensions of the enclosed unit for the TR 16

race car was referenced from Lai [6] as can be seen in Fig. 3. Similarly, the enclosed

domain for the diffuser and front wing is shown in Fig. 4 and Fig. 5 respectively.

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Figure 3. Enclosed Domain for TR 16 Race Car

Figure 4. Enclosed Domain for TR 16 Race Car

Figure 5. Enclosed Domain for TR 16 Race Car

Due to the complexity of the geometry of the race car as well as the aerodynamic

package, a tetrahedral mesh was incorporated. A coarse global mesh sizing relevance

center which produces a finer mesh surrounding the geometry of the model and enlarges

as the mesh moves further away from the model helps in reducing the overall number

L

2 L

2 L

4 L

2 L

3 m

3 m

8 m

10 m

0.55 m

0.385 m

2 m

1 m

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of elements for efficient computational time. The meshing result for the race car,

diffuser and front wing can be seen in Fig. 6, Fig. 7 and Fig. 8 respectively.

Figure 6. Coarse Mesh Sizing Relevance with Enclosed Body of 0.03 m Finer

Mesh

Figure 7. Coarse Mesh Sizing Relevance with a Sphere of Influence of 0.035 m

Finer Mesh

Figure 8. Coarse Mesh Sizing Edge Sizing of 0.00075 m and Seven Layer

Inflation of 0.00075 m

2.2.2 Numerical Method and Cases

The Reynold’s Averaged Navier-Stokes (RANS) k- , realizable turbulence

model with enhanced wall treatment was selected to simulate TR 16 as well as the

aerodynamic package. The k-, turbulence model is a suitable model as it can predict

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the recirculation and boundary layers under strong adverse pressure gradients or

separation caused by the geometry of the race car. The body of the TR 16 race car and

aerodynamic package and walls of the enclosed domain were set to no slip wall

condition whereas the symmetry plane was set to a symmetry condition. The inlet speed

was fixed at 17.88 m/s as the average speed of a Formula student race car across its

circuit is approximately 60 km/h. The outlet of the enclosed domain was set to an outlet

pressure of 0 Pa. The pressure far field option was not selected due to the intersection

between the wheels and bottom of the enclosed domain as configured by Lai [6].

There were three cases that were analyzed namely case 0, case 1 and case 2

which correspond to the non-aero assisted race, the diffuser and the front wing. In this

preliminary study, these are the cases that are concerned and the inclusion of the

aerodynamic package into the race car will be incorporated later as cases 01 with the

race car and the diffuser and case 012 with the race car, diffuser and front wing. Table

1 depicts the parameters concerned for case 1 and case 2.

Table 1. Parameters of Case Study

Case Parameter

0 Simplified TR 16 Race Car Model

Inlet (◦) Outlet (◦)

1

5 10

5 16

5 22

3 22

7 22

2

Pitch of Single wing Element

-3

8

13

Pitch of 2 wing elements

Main element (◦) Flap(◦)

0 10

0 30

12 10

12 30

2.2.3 Lap Time Simulator

To translate the performance of the TR 16 race car into quantifiable measures, an online

lap time simulator, namely FSAESim, is used to identify the lap times it can record

based on the four dynamic events. The four events are autocross, skidpad, acceleration

and endurance as well as its fuel consumption. The software utilizes the input of the

race car vehicle parameters to simulate a vehicle going around a track. Table 2

illustrates the TR 16 vehicle parameters that are input into the online lap time simulator

to compute the results of the lap time.

Table 2. Vehicle Parameters of TR 16 Race Car for Lap Time Simulation

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Vehicle Parameters Details

Tyre choice Hoosier 13” Large

Vehicle Weight (lb) 656.978

Wheel Base (in) 64.567

Wheel Radius (in) 6.5

Track Width (in) 50

Centre of Gravity (in) 12.992

Weight Distribution (%) 0.52

Shift RPM 11000

Final Drive Ratio 4.1

Engine / Curve Yamaha R6 – TU Graz Curve

Forced Induction Naturally Aspirated (o hp)

Aero Downforce at 40 mph 20.419

Lift/Drag Ratio 0.488

The results obtained from the lap time are set as a benchmark. The final

configuration of the race car with the aerodynamic package will be compared with the

benchmark to determine whether its performance will improve. The downforce and lift-

to-drag ratio of the diffuser and two element front wing will be input into the software

without changing the other parameters as seen in Table 2. This is to determine the

effects of the downforce and lift-to-drag ratio on the lap time recorded. This will serve

as the initial prediction that a higher downforce and increased lift-drag ration will

improve the recorded time.

3. Results and Discussion

3.1 TR 16 Race Car

The negative lift, or downforce and drag produced by the TR 16 race car is summarized

in Table 3. The =

> indicates that the race car has a relatively poor aerodynamic design

in which the amount of drag produced is almost twice as much as the downforce

produced at a speed of -?@AA m/s. This not only affects the fuel efficiency of the race

car, it also increases the time required to complete a lap.

Table 3. Summary of Results for TR 16 Race Car

Fig. 9 shows that most of the induced drag is formed due to the frontal area of

the race car exposed to the airflow as well as the tyres. By further analyzing the velocity

vector of the airflow along the surfaces of the race car, Fig. 10 indicates that there exists

a recirculation zone after the air passes the front and rear tyres which contribute to the

formation of wake and turbulence, and consequently induces more drag.

Downforce (N) Drag (N) =

>

90.830 186.018 0.488

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Figure 9. Static Pressure Distribution over the TR 16 Race Car

Figure 10. Velocity Vector around the Tyre of TR 16 Race Car

The effect of the downforce and drag acting on the race car is translated to a

more comprehendible manner in terms of lap time. Table 4 depicts the lap time recorded

based on each dynamic event by the TR 16 race car. Having identified the downforce

and drag produced especially the main areas which contribute to the drag of the car, a

suitable aerodynamic package can be designed to further increase the amount of

downforce produced whilst optimizing the drag. The lap time recorded as depicted in

Table 4 will act as the benchmark to determine whether the addition of an aerodynamic

package enhances the performance of the race car in terms of lap time reduction and

improved fuel consumption.

Table 4. TR 16 Race Car Recorded Lap Time Based on Dynamic Events

Downforc

e at 40

mph (lbf)

B

C

Dynamic Event Lap Time (s) Endurance

Event Fuel

Consumptio

n (gallons)

Autocros

s

Skidpa

d

Acceleratio

n

Enduranc

e

20.419 0.48

8 76.398 5.057 5.06 1512.389 2.44

3.2 Front Wing

3.2.1 Single Element Front Wing

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Fig. 11 shows the results obtained for the downforce and drag values at different

airfoil pitch or angle of attack. It can be seen as when the pitch of the airfoil increases,

the downforce and drag also increases. The flow velocity of air passing through the

bottom of the inverted Selig S 1223 airfoil is higher than the upper surface of the airfoil.

As a result, a difference of pressure is formed as can be seen in Fig.12. Hence,

downforce is produced. From the results obtained, the pitch of the airfoil that produces

the least drag, which is -3:, and the most downforce, which is 13:, is selected in

designing a two element front wing.

Figure 11. Downforce and Drag Produced on Different Airfoil Pitch

Figure 12. Pressure Contour Acting on the Single Element Front Wing with a

Pitch of 13:

3.2.2 Two Element Front Wing

The addition of a front wing not only produces downforce, it also serves to direct

the airflow above and away from the front tyres, thereby reducing the drag induced by

the tyres. A multi-element front wing consists of a main element and a flap. The option

of being able to manipulate the pitch of the flap enables a multi-element front wing to

produce more downforce as compared to a single element front wing.

Fig. 13 depicts the downforce and drag produced based on the various

configurations (main element_flap) of the two element front wing. It can be seen that

as the pitch of the main element increases from -3: to 13:, the downforce as well as

drag increases. The same can be said for the flap when the pitch increases from 10: to

30:. The obtained downforce and drag results are then input into the lap time simulator

to identify which configuration requires the least time to complete a dynamic event.

-3 8 13

Downforce 38.538 83.626 106.293

Drag 9.316 17.251 25.713

020406080

100120

Fo

rce

(N)

Pitch (◦)

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From Table 5, it is evident that the front wing with a 13: main element pitch and 30:

flap pitch produces the best lap time in all dynamic events.

Although this configuration produces the most drag, the effect of the downforce

is more significant. This is validated through Table 5 where it is observed that the lap

time recorded for each dynamic event reduces with an increase in downforce across

each different configuration. Therefore, the front wing with configuration main element

pitch of 13: and flap pitch of 30: is selected to be incorporated to the TR 16 race car.

Figure 13. Downforce and Drag Produced on Different Two Element Front Wing

Setup

Table 5. Lap Time Recorded Based on Two Element Front Wing Configuration

Downforce and ;

< Ratio

3.3 Diffuser

3.3.1 Diffuser Outlet Angle

Fig. 14 depicts the downforce and drag produced when the inlet angle of the

diffuser is fixed at 5:. When the outlet angle is 22:, maximum downforce and drag is

produced. This is a result of negative pressure being formed near the rear of the diffuser

as seen in Fig. 15. As air enters the inlet of the diffuser, it is accelerated through the

throat. The sudden decrease in velocity of the air when it starts to exit the throat towards

the outlet of the diffuser causes a drastic decrease in pressure. An area of vacuum starts

to form, causing turbulence and thereby producing drag. However, Fig. 16 shows that

flow separation does not occur until the airflow leaves the diffuser, ensuring that drag

-

3_10

13_1

0

-

3_30

13_3

0

Column1 58.816 81.414 102.762 131.165

Drag 10.86 18.741 26.396 37.504

0

50

100

150F

orc

e (N

)

Pitch / Angle of Attack (°)

Two Element

Front Wing

Configuration

Dynamic Event Lap Time (s) Endurance

Event Fuel

Consumption

(gallons)

Autocross Skidpad Acceleration Endurance

-3_10 76.837 5.093 5.070 1521.158 2.450

13_10 76.571 5.067 5.070 1515.840 2.430

-3_30 76.320 5.043 5.070 1510.818 2.440

13_30 75.995 5.012 5.060 1504.325 2.420

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does not occur within the diffuser. Hence, the configuration of the diffuser outlet is set

at 22:.

Figure 14. Downforce and Drag Produced against Varying Diffuser Outlet Angle

When Inlet Angle is Constant at 5:

Figure 15. Pressure Contour along Diffuser Model with Outlet Angle of 22: and

Fixed Inlet Angle of 5:

Figure 16. Velocity Contour along Diffuser Model with Outlet Angle of 22: and

Fixed Inlet Angle of 5:

3.3.2 Diffuser Inlet Angle

Fig. 17 depicts the downforce and drag produced at varying diffuser inlet angles

when the outlet angle is fixed at 22:. When the inlet angle is 3:, maximum downforce

10 16 22

Downforce 91.589 190.42 242.313

Drag 21.984 35.571 47.417

0

100

200

300

Fo

rce

(N)

Pitch (◦)

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and drag if produced. This is due to the bigger gap in pressure between the top and

bottom layer of the diffuser as seen in Fig. 18. A decrease in velocity as the air exits the

throat to the outlet of the diffuser created a large recirculation zone. This produced

higher a drag as compared to the case when the inlet is 5:. However, according to Jensen

[7] and Khokhar [8], if the inlet angle is too small, there will be no increment in the

airflow speed thus downforce is significantly reduced. Therefore, the inlet angle of 3:

is the most optimum configuration for this case.

Figure 17. Downforce and Drag Produced against Varying Diffuser Inlet Angle

When Outlet Angle is Constant at 22:

Figure 18. Pressure Contour along Diffuser Model with Inlet Angle of 3: and

Fixed Outlet Angle of 22:

Figure 19. Velocity Contour along Diffuser Model with Inlet Angle of 3: and

Fixed Outlet Angle of 22:

3 5 7

Downforce 253.628 242.313 215.452

Drag 49.651 47.417 45.203

050

100150200250300

Fo

rce

(N)

Pitch (◦)

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The diffuser configuration that produces the best result is when the inlet is 3:

with an outlet of 22:. This diffuser configuration recorded the least time taken to

complete all dynamic events except for the acceleration event. This is due to the

increase in drag as a result of the formation of wake and turbulence when the air exits

the diffuser. Hence, the diffuser configuration of inlet angle 3: and outlet angle 22: is

selected to be incorporated to the TR 16 race car.

Table 6. Lap Time Recorded Based on Diffuser Inlet Outlet Angle Configuration

Downforce and ;

< Ratio

4. Conclusion

The TR 16 race car was identified to have a relatively poor aerodynamic design.

The effects of an aerodynamic package, namely the diffuser and multi-element front

wing was studied numerically as well This is to enhance its performance in terms of

reducing the overall lap time of the race car and to increase its fuel efficiency. The

multi-element front wing produces more downforce as compared to a single element

front wing. When the pitch of the element increases, downforce and drag is also

increased. Furthermore, the multi-element front wing serves an additional function of

directing the airflow away from the tyre, thereby reducing the drag induced by the tyre

of the race car. The diffuser’s capacity to produce downforce depends heavily on the

inlet and outlet angle of the diffuser. A smaller inlet angle and larger outlet angle

corresponds to both a higher downforce and induced drag. This preliminary study

shows promise that when the diffuser and multi-element front wing is added to the TR

16 race car, a significant amount of downforce can be produced whilst maintaining an

acceptable drag limit. As a result, a better lap time can be recorded.

Acknowledgement

Throughout the duration of this research process, various guidance, help and

supervision was offered. A whole hearted gratitude and appreciation goes out to Tan

Zhe Xin, Muhammad Ammar Zulsyahmi and Farah Danial Rahman for their support

and assistance.

Nomenclatures

=

> Lift-to-drag Ratio

Diffuser Inlet

Outlet Angle

Configuration

Dynamic Event Lap Time (s) Endurance

Event Fuel

Consumption

(gallons)

Autocross Skidpad Acceleration Endurance

3_22 74.880 4.833 5.08 1482.028 2.41

5_22 74.920 4.899 5.08 1482.811 2.41

7_22 75.174 4.992 5.07 1487.904 2.41

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Abbreviations

FSAE Formula Society of Automotive Engineers

CFD Computational Fluid Dynamics

RANS Reynold’s Averaged Navier-Stokes

References

[1] Walter, D.J., (2007). Study of Aerofoils at High Angle of Attack , in Ground Effect.

Master's Thesis, RMIT University, Australia.

[2] Katz, J., (1995). Race Car Aerodynamics : Designing for Speed. Cambridge,

Massachusetts: Bentley Publishers.

[3] Wordley, S., Saunders, J., (2006) Aerodynamics for Formula SAE: Initial Design

and Performance Prediction. SAE World Congr., (1)724, 0806

[4] Merkel, J.P., (2013) Development of Multi-Element Active Aerodynamics for

the Formula Sae Car. Master's Thesis, University of Texas, USA.

[5] Zhang, X., Toet, W., Zerihan, J., (2006) Ground Effect Aerodynamics of Race

Cars, Annu. Rev. Fluid Mech., 1(38) ,27–63.

[6] Lai, S.A., (2016, December). Effect of Size and Shape of Side Mirrors on the Drag

of a Personal Vehicle. Paper presented at Taylor's University EURECA

Conference, Subang Jaya, Selangor.

[7] Jensen, K., (2010) Aerodynamic Undertray Design for Formula SAE. Master's

Thesis, Oregon State University, USA.

[8] Khokhar, A.A.S., Shirolkar, S.S., (2015). Design and Analysis of Undertray

Diffuser for a Formula Style Racecar. International Journal of Research in

Engineering and Technology, 4(11), 202–210