Aerodynamics in Formula 1 Racing Cars

1. INTRODUCTION AND PROBLEM STATEMENT
Aerodynamics is a wide field affecting the design of formula 1 (F1) race cars.
Aerodynamics affects all bodies moving through a fluid. The atmospheric
pressure affects the surfaces of the body. Pressure moves on the exterior
surfaces when the vehicle moves and changes as the velocity changes. These
changes in pressure introduces forces acting on the car surfaces that as a
result reduces its speed and reduces performance and lead to more fuel
consumption. Lift forces are as well introduced. When this happens, the car
becomes so light. Controlling the car becomes a problem. The tires are not
gripping the ground properly and breaking becomes difficult. This hinderance
and loss of traction is not a good property especially in racing cars and is
undesirable. As a result, race car engineers have to design car surfaces that
counter this phenomenon. One of those surfaces introduced to a racing sport
car is a back or rear wing. Once the design engineers have created a model,
they test the model in a tunnel of wind. A tunnel of wind is a very essential
part and idea in aerodynamic testing. It simplifies work as the model of the
car is held stationary while wind is blown towards the car. Sometimes the
wind tunnel may not be available. Engineers have to use a flow simulator to
learn some of the properties of the model or wing. This report aims at
describing the method and results obtained during a flow simulation exercise.
2. RESEARCH QUESTION AND OBJECTIVES
This assignment should answer the following questions.
a) What is the difference between the airplane aerofoil and the formula
one aerofoil?
b) What is the effect of attach angle on lift and drag coefficients?
c) What is the effect of addition of wing element to the drag and lift
coefficients?
d) What are the other properties that can be investigated by CFD other
than lift and drag coefficients?
e) Does change in surface roughness of the aero-wings affect the drag
force?
The objectives of this assignment are:
a) To design formula one’s car aerodynamic rear wing based on SAE 2018
regulations.
b) To analyze the lift coefficient and the drag coefficient of 3, 4 and 5
element rear wings.
c) To recommend the best wing deign.
3. HISTORY ABOUT FORMULA ONE.
The world formula one originated from the groups of rules and regulations that
all racers must adhere to. it was initially known as formula A. the race started
after the inter wars. The first race was arranged in the early 1930 but this plan
was halted by the world war 2. The hopes never ended there. In 1946, the year
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saw its first race. In the year 1947, the first championship for drivers was
discussed and planned. The preparations took another 3 months to be effective.
In the year 1950, the so awaited race took place in Silverstone. This doesn’t
mean that other formula one races didn’t happen between 1947 to 1950. There
were more than two dozen races happening in various places before the world
championship on May in Silverstone. But only less than 10 races in all those
were featured in the world championship. AT this time, the championship
formula one races were famous than the championship races. The non-
championship races were still famous until in the late 90s when they became
uneconomical.
All the time, drivers would buy their own vehicles and raced with them. This
were called privateers. Their presence was in abundance shortage of drivers was
never a problem. Most of the manufacturers of the formula car by 1950 were
Ferrari, Mercedes Benz, Ala Romeo and Maserati. All these companies were still
there even after the world war ii. The iconic player was Jan Manuel Fangio, who
won the world champions in the year 1951, 1954 and the consecutive three
years with various manufacturers. Guiseppe Farina won the year 1952 and 1953.
In the year 1952 and half the year 1953, there were less drivers or players
entering the competitions. This led to use of formula 2 regulations. The
championship was won by Alberto Ascari. By 1950, there were more than more
than two dozen players. However, by the year 1954, twenty of those players had
quite due to the high costs racing. Racing was never safe. From 1947 to
around1957, an interval of 10 years 13 drivers had died.
The cars in the pre seasons were run with front engines. A good example is the
Alfa’s 158. this had a capacity of 4.5 liter for the normally aspirated engines and
1.5 liters for supercharged engines. The car had car had narrow tires. Also. The
Formula Ones’ regulations forced engine capacities to 2500 cc in 1954. A
disaster happened in Le Mans in 1955 that made Mercedes Benz to withdraw
form all major sports. A rear engine car was introduced in 1958 by Cooper. The
rear engine was better than the front engine in a couple of ways. By 1961,
almost all car manufacturers had shifterd to the use of the rear engine. A
constructors’ championship was created in 1958 to add incentive for the teams.
British dominated most of the games during that era. This started with Mike
Hawthorns who won the championship in 1958. Other british who won the
championship are John Surtees, Denny Hulme, Jackie Stewart, Jim clark, Graham
Hulme and Jack Braham. They won the trophy in between themselves and only
one non british Stirling Moss came between them once. British won ten
constructors’ trophies and nine drivers’ championships from 1962 to 1963.
During the same span, the dominant formula one car was the British Green
Lotus. Its chassis was built with aluminum instead of using the olden space
frame chassis.
By 1970, the only man to win the driver’s championship frequently was Lotus
Jochen. He was clowned the new Lotus 1. He was replaced by Emerson Fittipaldi,
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a Brazilian who won the four consecutive races. Jackie Stewart took and Team
Tyrell took the championship in the year 1972 and 1974.
There was better method of production than the previous years. The formula
cars became much slicker and faster. Ground effects aerodynamics were
introduced by Lotus. The eeffects introduced big downforce pressing the formula
cars to the ground, enhancing road grip thus enabling high cornering speeds.
The racing costs become too high and non-profitable. This saw private racers
quit by 1970. There was also the invention of turbocharged engines which saw
formula one car have big speeds and powers being used.
Safety issues were never tackled and many drivers were injured. Francois Cevert
had an accident and died. Stewart never raced after the death of Ftancois, his
team mate. Formula one cars would sometime lose control and head towards the
spectators killing them or injuring them. Like the case of Fittipaldi in 1975 during
the Spanish Grand Prix. His car lost control and headed to the crowd0 killing four
of the spectactors.
Ferrari began to establish themselves in 1975 with the Clay Regazzoni and
Lauda Niki team and won the championship that year. Niki Lauda win six out of
the nine races he appeared before being involved in a gruesome accident that
injured him such that he was burnt all over, in 1976 at the German Grand Prix.
Though he was in the track again, he finished second after James Hunt.
Lotus led in 1978 again when the ground effects technology that used side skirts
and designs of the underbodies were introduced. This technology produced very
high grips than the other cars. Mario won six of the sixteen races he raced
because of this technology. His team mate was killed in Monza. Things started
falling apart for the Lotus team.
The introduction of wings and the idea of downward force happened on 1968 by
Colin Chapman. The wings were attached to the unsprang part of the formula car
and were very high. The end plates were used as support to the wing all down to
the chassis. This never worked as the end plates kept coming off at times and
lead to loss of controls and eventually accidents.
In 1970, the formula one management planned for commercial rights making the
sport into a global business. Bernie Ecclestone brought Brabhams’ team and
gained a position at the FOCA (Formula One Constructors Association) in 1971.
He became the president in the year 1978.
Another body called the FISA (Federation Internationale du Sport Aatomobile)
was formed and immediately were never in good term about the regulations and
revenues with FOCA. FOCA boycotted and the rivalry continued until 1981. They
were saved by the Concorde Agreement.
Williams and Alan Jones teams dominated in 1980. At this time for you to win,
you must had turbo. In 1988, a team called Zenit won 15 out of 16 races and
from that year turbo engines were abolished. There was the need to bring new
regulations on the engine power. By 1988, turbo engines had been banned
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altogether. During 1980s, there technology was advancing. Computer
motherboards were beginning t be used in formula one cars. Lotus group were
the first to use electronic driver aids. By 1990, traction control and the electronic
gearboxes were so common. During 1990 new racers McLaren and Williams
dominated. McLaren took 16 trophies.
In mid 90s, the race became more about the designers and the technicians than
the drivers. However, a few teams dominated: Renault, Williams and McLaren.
Ferrari has led from 1984 to 2008. FIA changed the championship rules
frequently. Team orders were banned in the year 2002 after FIA learnt that they
had been manipulating results. These changes saw other races such as Toyota,
Honda and BMW.
In 2004, the sizes of end plates were increased. The regulations put a minimum
size requirement for the end plates to increase the surface arears for putting
advertisements. In 2014, the Formula 1 car saw end plates beams banned and
the manufacturers were forced to make to look for ways to increase the strength
of the end plates without using many pylons. This is to achieve a good
aerodynamic characteristic and also for weight reduction.
4. LITERATURE REVIEWAerodynamics
It is a dynamic branch that deals with the study of motion when fluid passes
on or inside a body of an on object. It is divided into two; gas dynamics and
fluid dynamics. The two sub branches share a lot of theory in between them.
However, aerodynamics is much used with gas dynamics. To calculate the
forces and moments in aerodynamics, one need to understand the flow field
(motion of air) around an object. Properties investigated or calculated in
aerodynamics include pressure, wall temperatures, velocity and density, all
calculated with respect to time. (Nagoyoshi 2004).
Two dominant forces are involved in aerodynamics: drag forces and lift
forces. The administration of these powers is essential to the presentation of
any vehicle anyway the logic of vehicle streamlined features contrast
altogether relying upon the application. For example, the car and
transportation businesses look to limit the drag power to improve mileage at
thruway speeds. (Kourta, 2009). The aeronautics business looks to boost the
general effectiveness or lift separated by drag of their vehicles. The more lift
created, the bigger burdens the air ship can convey and the littler drag power
considers better fuel utilization. (Roumeas, 2008)
In spite of the fact that the streamlined plan methods of insight may contrast
dependent on principles and guidelines, when all is said in done, engineers
look to boost negative lift or down power inside some reasonable drag limit
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which is dictated by a mix of top speed and fuel necessities. Expanding the
downforce on the vehicle builds the typical burden on the tires which means
an expansion in by and large cornering hold and similarly in general
execution and decrease in lap time. (Iljaz, 2006)
Joseph Katz remarks that, "streamlined downforce has as of late been
comprehended and utilized effectively in the previous 40 years" (Katz 2009).
The principal streamlined gadgets utilized for dashing applications happened
around 1960 where the pattern first begins to increment strongly. He likewise
takes note of that around 1970 was the primary proficiently planned optimal
design bundle for a dashing application which brought about another
enormous increment in lap speed (Katz 2009).
Engineers try to look for negative lift force to enhance traction and grip.
Expanding the downforce on the vehicle builds the typical burden on the tires
which means an expansion in by and large cornering hold and similarly in
general execution and decrease in lap time. (Pfeiffer 2019)
Joseph Katz remarks that, "streamlined downforce has as of late been
comprehended and utilized effectively in the previous 40 years" (Katz). The
principal streamlined gadgets utilized for dashing applications happened
around 1960 where the pattern first begins to increment strongly. He likewise
takes note of that around 1970 was the primary proficiently planned optimal
design bundle for a dashing application which brought about another
enormous increment in lap speed (Katz).
Aerodynamic fairings that are used in a racing car such as F1 are the front
wing, the diffuser and the back wing. (Zikanov 2010)
The front wing produces enormous downforce and uses multi element design
in most F1 cars (although this depends with the rules of the sport). To
minimize the tip loss, end plates which vary in size and shape are used. The
front wing is the most important design feature of a F1 since it determines
hoe air is distributed to the rest surfaces of the vehicle. Poor design of drag
wings lead to extreme drag force of the car. They also dictate the placement
and size of the rear wing. (Katz 2009)
A diffuser is an underbody device that seeks to make us of the underbody
produced by a racing car. It mostly reduces lift. Tunnels, flat surfaces and
stepped underbody are utilized by the diffuser.
The rear wing is used to alter the lift and drag forces. They can be single or
multi-level just like the front wing but this depends on the rules being
followed. They have a bif endplates to minimize tip loss.
In F1 the back wings and the front wings are completely on the opposite side
of the gravity point (F1, 2010).SAE rules governing Aerodynamics.
SAE rules that governs the Aerodynamics of F1 are.
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“T9.2 Location - In plain view, no part of any aerodynamic device, wing, under tray or
splitter can be:
a. Further forward than 762 mm (30 inches) forward of the fronts of the front tires
b. No rearward further than 305 mm (12 inches) rearward of the rear of the rear tires.
c. No wider than the outside of the front tires or rear tires measured at the height of the
hubs, whichever is wider.
T9.3 Minimum Radii of Edges of Aerodynamic Devices - All wing edges including wings,
end plates, Gurney flaps, wicker bills and undertrays that could contact a pedestrian
must have a minimum radius of 1.5 mm (0.060 inch)
T9.4 Ground Effect Devices – no power device may be used to move or remove air from
under the vehicle except fans designed exclusively for cooling. Power ground effects are
prohibited.”
(SEA international, 2018-2019)
According to SAE Active aerodynamics are any device on top of a wing or a
movable surface that change their orientation or location or position as a
result of drivers input or any other controller input. Electric systems are used
with true active aerodynamics while others do depend on the drivers input.
Active aerodynamics can be grouped into street vehicle active aero and
racing car aerodynamics. The difference between the two is on the type of
vehicles they are used on. The street active aero are sed to increase
efficiency, reduce drag and traction of street cars while the latter is installed
to racing cars. They help the car when negotiating bends and breaking. The
close downwards when the car is breaking or negotiating corners to increase
drag and open to allow more flow easily when accelerating (McBeath, 2006).Multi-element wing
Use of multi-element wings for SAE cars started in 2013. They consist of a
slat, a main element and flaps. A three elements wing has a slat, a flap and a
main. Four elements wings have a slat a main and two flaps. Five elements
wings have a slat, a main and three flaps. Computational Fluid analysis is
used to calculate the simulation data. The flow simulator generates a mesh.
Lift and drag forces are iterated until they converge.End plates.
Endplates is a major assembly on the rear wing. This is the wing part that
supports the wing elements. They are always two. Design considerations
made to when designing these support structures are weight considerations
and strength considerations. Engineers must balance between the two.
Endplates influences the manner which air flows over the wings. To reduce
the vortices formed by end plates and to increase their efficiencies, endplates
nowadays are slated.
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(Urlings, 2016)
These loop holes made on the end plates also have the effect on drag and
downwards forces. The slats are usually 50 mm in width. Its shape therefore
matters a lot.Lift forces
This is the upward forces caused by flow of air around an object. It is a
component of wall shear force and pressure. It moves the body in the
direction of the shear force and the air pressure. If the lift coefficient is
negative, then the lift force will be negative and will press the car downwards
preventing it from flying. This is actually the essence of wings in a car (to
prevent flying). This force is generated by the pressure difference between
the top and bottom surfaces of the wing. Density, velocity of the fluid, shape
and size of the object affects the lift force.
The lift coefficient is defined as
FL = Cl pVxV x A
2
Where A is the area of the object subjected to the flowing fluid.
½ pV2 is the dynamic pressure while FL is the lift force. (Toet, 2013)
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(Toet, 2013)Drag force.
It is the force of aerodynamics opposing the forward velocity of the object
moving in a fluid of air or liquid. The speed differential between the object
and air is directly proportional to the drag force. It comes in forms such as
friction force on the object surface and air resistance. This is the friction
between the molecules of air with the solid molecules of the wing. Rough
surface produces more friction than smooth surface. This viscosity changes
with the viscosity of the fluid and the viscous force relative magnitude of
motion. It is expressed Reynold’s number. On the surface of the solid a
boundary layer is created. This boundary layer affects the skin friction
magnitude. (Kajiwara, 2017).
The other component of drag force is the air resistance. It is affected by the
shape of the wing. Pressure and localized forces are altered effectively
generating a force around the body. The change of air direction about the
aerodynamic devices creates a vortex at the locations where the changed
airflow meets the streamlined (unchanged) airflow. Interference drag also
called induced drag is due to vortices produced behind the body. (Kajiwara,
2017)
Wave drag and ram drag are other forms of drag forces. Ram drag occurs
when the airstream slows down when the air is passing through an inlet.
Wave drags happens when a moving object accelerates to the velocity of
speed. It is uncommon for formula cars to reach the speed of sound thus
wave drag is unimportant. (Zhigang 2011).
Drag coefficient is a constant that quantifies the amount of drag. It is a ratio
of drag caused by drag force to the product area of the body and the air or
dynamic pressure. It is abbreviated as Cd. the figure below shows the various
types of drag coefficient.
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