aerodynamics in action formula one cars

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A Paper on AERODYNAMICS IN ACTION FORMULA ONE CARS Presented at TECHNOFEST-2010 Organized by VRSEC Presented by Krishna Kanth KVSS [email protected] Ph No-9553794862 Department of Mechanical Engineering Jawaharlal Nehru Technological University Kakinada East Godavari Andhra Pradesh -533 003

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Page 1: Aerodynamics in Action Formula One Cars

A Paper on

AERODYNAMICS IN ACTION

FORMULA ONE CARS

Presented at TECHNOFEST-2010

Organized by VRSEC

Presented by

Krishna Kanth KVSS

[email protected]

Ph No-9553794862

Department of Mechanical Engineering

Jawaharlal Nehru Technological University

Kakinada

East Godavari

Andhra Pradesh -533 003

India

Page 2: Aerodynamics in Action Formula One Cars

Index

Aerodynamics in Action-Formula One cars

-Abstract

-Introduction

-Earlier Developments

-F1 configuration

-Streamlining the body

-Downforce

-Base Design

-Front wing

-Rear wing

-The high nose

-Diffuser

-Angle of attack

-Conclusion

-References

Page 3: Aerodynamics in Action Formula One Cars

Aerodynamics In Action

Formula One Car

Abstract

Aerodynamics in Formula One racing is often described as a black art, the real secret to success

on the track .In the tough struggle for crucial seconds in Formula 1, aerodynamics play a

fundamental role .Small impact make the difference between success and failure. A small

change in aerodynamic structure can make the difference. A modern formula one car is a

technical master piece. Aerodynamics in formula one deals with how effectively we utilize the

air, in favor of requirement of us and not considering it as a frictionally force .Any person

driving his/her car at 120-150 KMPH finds it very difficult to control it. But any one has ever

imagined how difficult it is to control a car at 300-350 KMPH on road. Practically not possible,

but it is all made to work by aerodynamics. With the available technology it is not difficult to

manufacture an engine which can run at speed on par with the speed of sound or even greater,

but the thing is how effectively a driver controls it on the road. There the role of aerodynamics

comes into play. In a sport obsessed with attention to detail, the aerodynamicists are more

obsessive than most. The teams invest up to 20% of their total budget in the science of the

winds, making their cars even faster with innovative aerodynamic designs. Meticulous

precision work is undertaken down to the last millimeter, according to the motto; races are won

in the wind tunnel and lost on the track.

INTRODUCTION

First and foremost, aerodynamics is the science of manipulating and making use of airflow. Put

simply, aerodynamics deals with the flow of air and how it reacts with bodies in motion. A

windmill and an aero plane are both examples of aerodynamics in action. In Formula One

Page 4: Aerodynamics in Action Formula One Cars

racing, high speeds means the air is a formidable force presenting an obstacle to speed but it can

be used to the car’s advantage as well. The following deals with different parts of the formula

one car aerodynamically streamlined so as to get maximum performance on the track. The

paper entirely revolves around the downforce developed on the car

Early Development

In the 1960's the use of soft rubber compounds and wider tyres , demonstrated that good road

adhesion and hence cornering ability, was just as important as raw engine power in producing

fast lap times. The tyre width factor came as something of a surprise. In simple school

experiments on sliding friction between hard surfaces, the friction resistance force is found to

be independent of the contact area. It came as a similar surprise to find that the friction could be

greater than the contact force between the two surfaces, apparently giving a coefficient greater

than one. The desire to further increase the tyre adhesion led the major revolution in racing car

design, the introduction of inverted wings, which produce negative lift or 'down force'. Since

the tyres lateral adhesion is roughly proportional to the downloading on it, or the friction

between tyre and road, adding aerodynamic down force to the weight component improves the

adhesion.

F1 configuration

F1 can be considered to be canard configurations in the sense that the front and back wings are

on opposite sides of the centre of gravity and both are "lifting" (strongly) in the same direction,

in this case down. The car should be considered in (at least) 3 parts; front wing, body and rear

wing. Each of these parts should be optimized for down force (i.e. "lifting" down) and low drag,

with the accent very definitely on down force. This down force can be likened to a "virtual"

increase in weight, pressing the car down onto the road and increasing the available frictional

force between the car and the road, therefore enabling higher cornering speeds. This allows

today's formula-1-cars to withstand centrifugal forces from 4G as to where a passenger car with

sport chassis begins to slip at 1G.

Page 5: Aerodynamics in Action Formula One Cars

Streamlining the body

An important aspect of aerodynamics is the drag, or resistance, acting on solid bodies moving

through air. The drag forces exerted by the air flowing over the car must be overcome by the

thrust force developed by the engine. These drag forces can be significantly reduced by

streamlining the body.

A streamlined shape is one with a contour that is itself a streamline (such as the airfoil below),

or its shape is such that its resistance to the flow of air, water, or another fluid past it is

minimized. So when we talk about streamlining a body, we are trying to smooth out the

external contours of the shape to create a streamlined flow over it and reduce the flow's

resistance to that motion. This resistance is what we call drag, and this particular kind of drag is

referred to as form drag. For bodies that are not fully streamlined, the drag force increases

approximately with the square of the speed as they move rapidly through the air. The power

required, for example, to drive an automobile steadily at medium or high speed is primarily

absorbed in overcoming air resistance. The more streamline a vehicle is, the less power it needs

to obtain high speeds, and therefore is more economical.

Page 6: Aerodynamics in Action Formula One Cars

Downforce

Aero foils in motorsports are often called wings, referring to aircraft wings. In fact they are very

similar. F1 wings and winglets aim to generate high downforce, by having a high angle of

attack, thus also increasing the drag of the aerofoil. The evolution of an airfoil to what it is now

is mainly thanks to Bernoulli and Newton, who initially had totally different views on

generating downforce. When a gas flows over an object (or when an object moves through a

gas), the molecules of the gas are free to move around. They are not closely bound to one

another as in a solid. Because the molecules move, there is a velocity (speed plus direction)

associated with the gas. Within the gas, the velocity can have very different values at different

places near the object. Bernoulli's equation relates the pressure on the object to the local

velocity; so as the velocity changes around the object, the pressure changes as well, in the

opposite way.

Bernoulli Newton Today

Now adding up the velocity variation around the object instead of the pressure variation also

determines the aerodynamic force. The integrated velocity variation around the object produces

a net turning of the gas flow. From Newton's third law of motion, a turning action of the flow

will result in a re-action (aerodynamic force) on the object. So both "Bernoulli" and "Newton"

are correct. Integrating the effects of either the pressure or the velocity determines the

aerodynamic force on an object. These two equations have lead to the current airfoils used and

make optimal use of both theories.

Page 7: Aerodynamics in Action Formula One Cars

Base Design

Formula One reverses the principles behind an aeroplane wing.In simple terms, an F1 wing is

designed so that air flows more rapidly over its lower surface than the upper. This creates an

increase in pressure on the top surface compared to the bottom. The resulting pressure

difference creates a downward pressure, which we call downforce.This relatively simple

concept is made more complex by the relationship between downforce and drag. A wing is so

designed that air flows more rapidly over its upper surface than its lower one, leading to a

decrease in pressure on the top surface as compared to the bottom. The resulting pressure

difference provides the lift that sustains the aircraft in flight. If the wing is turned upside-down,

the resultant force is downwards. This explains how performance cars corner at such high speed

The 'downforce' produced pushes the tyre into the road giving more grip.This down force helps

the car to firmly grip to the ground. During the turnings of the car the down force compensate

to the high centrifugal force on the car giving it high stability. This makes the car to achieve

high speed. A modern Formula one car when travelling at high speed can produce a down force

which is sufficient for the car to go upside down on the roof of a construction.

Front Wing

The front wing is vital to the entire car, as it is the first part to come in contact with the air, and

must be able to leave it relatively undisturbed, whilst producing sufficient downforce for grip

on the front tyres . It affects the airflow down the full length of the car and even tiny changes

Page 8: Aerodynamics in Action Formula One Cars

can have huge effects on the overall performance. The front wing accounts for approximately

33% of the total car downforce. The front wing end plates reduce drag and also direct air over

the front wheels in attempt to reduce the drag.

The front wing is shaped to direct air to the underside of the car and ultimately feed the

undertray. Shaping is also employed to allow air to cool the brakes and radiators. The front

wing is a compromise between producing downforce and directing air to other areas of the

car.The front wing of a Formula One car is held by two vertical connectors, which also act to

shape the airflow underneath the car. The front wing consists of either two or three components,

all of which are Shaped and angled to produce the most downforce with the least amount of

drag. Each component is adjustable, such that its angle of attack can be altered to suit different

circuits, or even during a race in order to deal with understeer or oversteer. Whilst covers over

the wheels which sit on either end of the front wing, styled to direct airflow over the wheels

such that there is less turbulence as it travels over the rest of the car. Modern endplates often

have smaller wings protruding from the outside, producing a small amount of extra downforce

and aiding the correction of airflow.

Page 9: Aerodynamics in Action Formula One Cars

Rear wing

The rear wing helps glue the rear wheels to the track, but it also hugely increases drag. This

means designers are constantly working to use as little angle of incidence on the rear wing as

possible without harming overall performance.The basic principle of a formula one wing is

exactly the same as with a common aircraft. The greatest difference is the direction air is

pressed and how that aerodynamic force is generated. Knowing that an aircraft wing does the

opposite of an F1 wing, the formula one wing is explained. With a single wing, we do not have

to think about turbulence that is generated by the car itself (the engine cover mainly), neither do

we have to take in account the direction and speed of outside wind. It is obvious that both these

factors decrease the efficiency of an aerofoil. As you can see in the picture above, air flows

onto the rear wing with a straight direction (which is often called clean air) at the speed of the

car. The white flaps push the air up. Following Newton's law, an action causes a reaction,

which is why the aerofoil is being pushed towards the ground by the air. Having in mind that air

flowing onto the flaps is pushed upwards, and underflowing air keeps going its own way, a low

pressure area (nearing a vacuum at very high speeds) is created right behind the horizontal

aerofoils. This 'vacuum' causes a suck up of the air passing under that flap. The underpassing

air on the other hand again flows faster in an attempt to equalize pressure on both sides of the

aeleron, and thereby increasing the total wing efficiency. Because of the car's speed this is

Page 10: Aerodynamics in Action Formula One Cars

impossible, which is why the effect is maintained. The force that is created by this type of wing,

so that the car is pressed onto the ground, is called downforce.

The high nose

The nose cone of formula one car is similar to the nose cone of a modern aircraft .The main

advantages of a higher nose need some thinking and knowledge of the complete car to see. At

first sight the higher nose is equal to less downforce as by itself it pushes less air up over the

nose. Surprisingly the nose is not aimed to push air up, but instead small at the front to allow

air flow aside of the nose. The air that passes the nose forms the basic concept of a high nose

cone. Having such a nose allows air to go straight through under the nose instead of having to

bend around it. While it reduces drag for sure, the front wing planes can span the complete

width of the car which in fact allows more downforce to be generated at the front. All air that

passed under the nose is then guided under the car or split to either side of the car by the splitter

located just in front of the sidepods. But the sky is not all blue as there are also some

disadvantages to it. The nose itself of course does not generate much downforce; in fact the

higher the nose point the less downforce by itself (this does not include any downforce

generated by front wing or floor). Another disadvantage for the highest noses may be visibility

from the driver's point of view

Page 11: Aerodynamics in Action Formula One Cars

The diffuser

The smallest thing which can count to the wings part is the

diffuser. Actually, it does exactly the opposite of a rear or

front wings. Instead of pushing the air up, it sucks the air

up. The volume of the diffuser increases towards to the

end of the car. Where a certain amount of molecules filled

for example 1dm³ under the car, these now fill 2dm³. This

drop of pressure causes a car to be sucked towards the

ground. Driving at a speed of 300 km/h, the ground effect of the car would be extreme if there

was no air under the car itself. Instead of raising the back of the car, the diffuser sucks the air

away from under the car because the low pressure. The diffuser is placed under the rear wing

and is actually a sweep up of the car's floor. It consists of many tunnels and spliters which

carefully control the airflow to maximize this suction effect. The design of the bottom of the

car, and thereby the diffuser is a critical area, because it can greatly influence the car's

behaviour in corners. More importantly, the designers have to be carefull that the car keeps

working well in all circumstances, and at any distance from the ground. Losing all of the

diffuser's generated downforce when riding over a curb will greatly generate a nervous

behaviour of the car itself. The strokes and flips withing the diffuser have lately become that

advanced that any track distance is insufficient to guarantee good performance. It is still a part

where a lot of time can be gained on current F1 cars, partly by pulling more air towards the

diffuser.

Angle of attack

Every part of the formula one car is assembled in such a way that it is at a certain angle to the

horizontal. The angle may be 0 degrees or above. This angle is called angle of attack. It is

called so because it is the angle at which the any part of a car faces the air. The angle of attack

depends on the situation on the day of race. It depends on the temperature, humidity of air, the

velocity of air, the direction of air flow (is it in the direction of track or opposite to it) and many

other reasons. The angles are set on the day of the race. These angles are decided by the

expertises because only immense experience can make you decide which angle to set. There are

Page 12: Aerodynamics in Action Formula One Cars

no specific formulas or calculations to set the angle. Further more the change in angle of one

part will effect the functioning of another part. For example if we change the angle of nose cone

it deviate the air at different angle to the rear wing. Intern the rear wing has to be adjusted so as

to face the air properly. In this way change in a single part lead to the change in efficiency of

other parts. The front wing is normally kept at an angle between 0 to 15 degrees. The rear wing

is adjusted between 20 to 65 degrees depending upon air flow. The nose cone is kept at an angle

between 30 to 50 degrees. Every angle depends upon the day of race.

Concurring

It is the most nail biting war in formula one race. Every formula one car is designed in such a

way so as to face normal air and produce downforce through it. But when a formula one car is

behind another formula one car it donot face normal air as the front car does. The air it faces

will be highly turbulent in flow which is coming out of the diffuser of the car. This makes the

behind car inefficient to produce sufficient downforce so as to overtake the forward car. It is

this reason why the formula one regulating authority has imposed regulations on the diffuser of

the car. The diffuser has been widened at its end so as to facilitate the air to strike the behind

car effectively. Projector like things are also provided behind the car so as to divert it exactly in

the same way the car is facing the air But this is not the final solution to it and the

aerodynamists are working on this to decrease the problem

Conclusion

With the available technology of powerful engines, electronic transmissions it is easy to attain

high speeds but the problem is with the stability of the car on the track. until and unless a

proper aerodynamic design is added to the car outer built it cannot resist to the lift and

centrifugal forces produced on the car at high speed .without the advancement in aerodynamics

there is no improvement in downforce and without downforce there is no high speed stability

and without it we cant imagine a formula one race .That means without aerodynamics there is

no formula one.

Page 13: Aerodynamics in Action Formula One Cars

References

BooksThe ultimate encyclopedia on Formula one by Bruce Jones, Damon hill

Internet

www.f1technical.comwww.wikipedia.org