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DANIEL BAKER | YEAR ONE PROJECT | NORTHBROOK COLLEGE |2012/13
COURSE LEADER: MR. DAVID TUCKER
FDENG
MOTORSPORT
ENGINEERING...
[INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013
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Table of Contents
1. Introduc...
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6.2 Shape Defining Innovation...
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INVESTIGATION INTO THE AERODY...
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From a personal pointof view ...
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Figure 2.1 f1-country.com
Dow...
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Figure 2.2 www.avalanche-cent...
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2.3 Drag
Any object that is s...
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2.3.1 Viscosity
An important ...
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as skin friction drag. The mo...
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2.4 Lift/Downforce
The main ...
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This pressurecoefficientcan ...
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have a far greater impact on...
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3. History ofFormulaOne Desi...
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The implementation of safety...
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a means of producingfar grea...
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producingnear 1200BHP, leadi...
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4. The FormulaOne Car
So as ...
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The crucial rolethataerodyna...
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being put into analysingever...
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From a set up point of view ...
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In the sameway that downforc...
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will obviously need to negot...
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sizeand location,as well as ...
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5. DesignProcess
There are v...
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incorporateinto the new desi...
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However before the construct...
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CFD has become such a powerf...
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR
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INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA ONE CAR

  1. 1. DANIEL BAKER | YEAR ONE PROJECT | NORTHBROOK COLLEGE |2012/13 COURSE LEADER: MR. DAVID TUCKER FDENG MOTORSPORT ENGINEERING INVESTIGATIONINTO THE AERODYNAMICDESIGN OF A FORMULA ONE CAR
  2. 2. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 1 | P a g e Table of Contents 1. Introduction.....................................................................................................................................................................3 2. Aerodynamics ..................................................................................................................................................................5 2.1 Bernoulli’s Equation..............................................................................................................................................5 2.2 Streamlines.............................................................................................................................................................6 2.3 Drag.........................................................................................................................................................................7 2.3.1 Viscosity..............................................................................................................................................................8 2.3.2 Boundary Layer.................................................................................................................................................8 2.3.3 Skin Friction Drag..............................................................................................................................................8 2.3.4 Form Drag ..........................................................................................................................................................9 2.3.5 Induced Drag.....................................................................................................................................................9 2.4 Lift/Downforce....................................................................................................................................................10 2.4.1 Coanda Effect.................................................................................................................................................11 2.5 Slipstream/Wake................................................................................................................................................11 3. History of Formula One Design..................................................................................................................................13 3.1 The Early Days.....................................................................................................................................................13 3.2 Safety and Chassis Design Revolution............................................................................................................13 3.3 Aerodynamics Arrive.........................................................................................................................................14 3.4 Pushing Design to the Limit..............................................................................................................................14 3.5 Turbo Era .............................................................................................................................................................15 3.6 Modern Day.........................................................................................................................................................16 4. The Formula One Car...................................................................................................................................................17 4.1 Makeup of an F1 Car..........................................................................................................................................17 4.2 Aerodynamic Package.......................................................................................................................................17 4.2.1 Front/Rear Wings...............................................................................................................................................18 4.2.2 Floor and Diffuser...............................................................................................................................................20 4.2.3 Other areas..........................................................................................................................................................21 5. Design Process..............................................................................................................................................................24 5.1 Initial Design/Conception .........................................................................................................................................24 5.2 CAD ...............................................................................................................................................................................25 5.3 CFD................................................................................................................................................................................26 5.4 Wind Tunnel................................................................................................................................................................27 5.5 Simulation....................................................................................................................................................................27 5.6 Testing..........................................................................................................................................................................28 5.7 Development...............................................................................................................................................................28 6. Design Innovations over the Years............................................................................................................................29 6.1 Chapman Legacy.................................................................................................................................................29
  3. 3. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 2 | P a g e 6.2 Shape Defining Innovations..............................................................................................................................29 6.3 Short-lived/Banned Innovations......................................................................................................................30 6.3.1 Brabham Fan Car...........................................................................................................................................30 6.3.2 Ground Effects ...............................................................................................................................................30 6.3.3 Active Suspension..........................................................................................................................................31 6.3.4 Mass Damper .................................................................................................................................................31 6.3.5 X-Wings............................................................................................................................................................31 6.4 Recent Innovations ............................................................................................................................................32 6.4.1 F-Duct ..............................................................................................................................................................32 6.4.2 Blown Diffuser................................................................................................................................................32 6.4.3 Double Diffuser..............................................................................................................................................32 7. Conclusion.....................................................................................................................................................................33 Critique...............................................................................................................................................................................36 References...............................................................................................................................................................................37 Bibliography............................................................................................................................................................................38
  4. 4. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 3 | P a g e INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR 1. Introduction From the very outset of this projectI was tasked with undertakingfor the Fd.Eng Motorsport Engineering I had decided to base my work around the subjectwhich I am most passionateabout,Formula 1, and a subjectwhich I am keen to learn more about and improve my skillsatin,aerodynamics and the use of tools such as CAD and CFD in the field.Initially theaim of the projectwas to ‘Research and design a Closed Cockpitand Wheel Cover systems for use in Formula One, with the aimof improvingdriver safety and overall car performance ’. However after performing the initial research into this area of Formula One design it became apparent that the information readily availablesurroundingthis area of driver safety was primitiveat best, meaning itwould have been difficultto discuss and design such a solution in greatdetail.Therefore as opposed to simply focusingmy projecton one singledesign area I have decided to further quench my appetite for Formula One by lookinginto the overall design philosophy of the modern day Formula One car and the ways in which tools such as CAD and CFD are used to move these designs from the mind into reality. So For my year one project I have decided to undertake an investigation into the aerodynamic design of the modern Formula One racecar as well as the process that is followed by many teams up and down the grid in the world of Formula One in order to produce this monumental feat of engineering. For the purposes of this projectI have firstly looked into the theory of aerodynamics as a concept, lookinginto the reasons why it affects the flowof air and how this theory is put to useto produce downforce on a body. Followingon from this initial groundingin aerodynamics, the ways in which the design of a Formula One car works to produce downforce was studied. Research was carried out into the overall makeup of the modern day F1 cars aerodynamic packageand the many different steps that are involved in design process,allowingme to look into the various design tools and methods that are put to use by the engineers and designers of the F1 world in the pursuitof creatingthe fastestcar possible. The aerodynamic design of a Formula One car has progressed ata rate so substantial thatthe cars we saw lineup in the early years areunrecognisablefrom the ones we see today. The massiveadvancements in technology alongsidedesign innovations year after year have transformed the Formula One car from its initial conception in the 1950’s,when essentially itcomprised of simply four wheels with the best engines of the day strapped to the front with littlethought given into the driveability of the vehicle,to the precisefeats of aerodynamic engineering that make up the Formula One cars thatwe see today. This radical changein design over the decades has been made possibleby the advancements in design methods and tools used in the sport, completely redefining the process in which design engineers followwhen creatingthese pieces of art. The changingfaceof the Formula One car over the years is the resultof vastamounts of progress that has been made in aerodynamic design of the car,with many innovations creatingthe definingimage that we see on the modern F1 car. As a resultof this changeI will bebriefly discussingthehistory of the Formula One car,allowingmeto research into the theory behind many of these innovations thatlead to the change in design over the years and the issues which resulted in the cars lookinglikethey do today. Havingresearched the basic conceptof aerodynamics and how this theory was put to usein the aerodynamic design of a Formula One car pastand present, I will finish up by havinga look into some basic aerodynamic analysisin an effort to put what I have learned over the courseof the project into practice,providinga concludingchapter to my research.
  5. 5. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 4 | P a g e From a personal pointof view I have always been fascinated by the way in which the most talented Formula One designers are ableto envisageingenious ideas to unlock performance in areas of the car that many thought was not possible,which in many cases involves ‘bendingthe rules’.For this reason I will be lookinginto several of the technical innovations thathave cropped up over the years in the pursuitof speed, most of which have subsequently been banned, but are none the less fascinatingfeats of engineering. Finally havingundertaken the research into this world of Formula One design I will hopefully be ableto gain a far great understandingof the ways in which designers come up with new ideas and move them from the drawingboard onto the racecar for real,sometimes in the pursuitof gainingfractions of a second. This greater understandingwill stand me in good stead to progress my knowledge of tools such as CAD, and looking further afield, CFD, that sections of this projectwill bebased around and an area that I am keen to work in in future years.
  6. 6. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 5 | P a g e Figure 2.1 f1-country.com Downforce 2. Aerodynamics Aerodynamics is the singlemostimportant factor in the performance of a Formula One car, with the concept being put to use in the design of the cars to produce the astonishingcorneringspeeds the modern car is capableof. Aerodynamics itself is the motion of air around an object and the forces that this creates. In this chapter the various theories and phenomena’s upon which aerodynamics is based and the ways that the concept is ableto produce forces such as downforce will bediscussed. 2.1 Bernoulli’s Equation The fact that the Formula One cars we see today are capableof such high corneringspeeds due to aerodynamics is in many ways thanks to the work done by one man, Daniel Bernoulli,way back in the 1700s. The concept of aerodynamics and the laws,upon which itabides by, are as a resultof the famous equation that Bernoulli derived duringhis study of moving fluids and the forces actingupon them all thoseyears ago. A Formula One cars aerodynamic performanceis gauged and improved upon by use of the formula, which details the relationship between fluids,of which air is,speed and pressure. There are many different variations of Bernoulli’s formula;the form that is relevantto the downforce that a Formula One car produces is as follows: 𝑃𝑠 + 1 2 𝜌𝑉2 = 𝐶𝑜𝑛𝑠𝑡𝑎𝑛𝑡 = ′ 𝑇𝑜𝑡𝑎𝑙 𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒′ 𝑃𝑠 = 𝑆𝑡𝑎𝑡𝑖𝑐 𝑃𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝜌 = 𝐴𝑖𝑟 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 𝑉 = 𝐹𝑙𝑜𝑤 𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 From this formula we can see that any increasein pressurewill resultin a decreasein the velocity, as the resultingforce is always a constant. Therefore the oppositewill also betrue; meaning an increasein velocity would lead to a decrease in pressure.It is this lawof aerodynamics that explains theways in which aerofoils,or wings,areableto produce liftor downforce. This incompressiblenatureof the fluid results in the pressureand velocity differences that produce the downforce from a Formula One wing. As air flows simultaneously over the upper body and beneath the underside of the wing, the velocity of each of the streamlines of air changes.The air flowingunder the wing will followthe curvature of the wing to meet with the upper stream at the trailingedge. This turning on the underside, as shown in figure 2.1, will lead to an increasein airspeed,meaning its velocity will increase.The increasein velocity will createa lowpressurezone under the wing, with the slower velocity of the streamlineon the upper body of the wing creatinga higher pressurezone. The air will then be attracted towards this area of higher pressureon the top of the wing, pushingthe wing towards the ground and as a resultcreatingdownforce. The way in which Bernoulli’s equation is used by an aerofoil to produce downforce can be transferred to the entire design of a Formula One car, with the aimof creatinga faster flow of air on the underside of any surfaces,or for that matter the entire car, than that flowingover the top of the samesurface.From here we can concludethat the faster air flowon the undersidewill resultin downforce being produced.
  7. 7. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 6 | P a g e Figure 2.2 www.avalanche-center.org 2.2 Streamlines The concept of aerodynamics revolves around the streamlines of air that pass over an object that is in motion. This streamlines arethe image that most will visualizewhen thinkingof aerodynamics and can be seen with use of smoke injection in a wind tunnel. As air flows over an object, itdoes so in layers.These layers are known as beingeither attached or separated from the object and the better the aerodynamic shapeof an object, the more attached the layers will be. Keeping the layers attached to the object as they flowover itis vital in reducingthe levels of drag created as well as helpingto create greater levels of downforce. This is because if the air was to become separated then the layer of air would become turbulent and flow separation would occur.This can have the resultof creatingeddies and vortices in the air flow that causean up wash, which would have a detrimental effect on the aerodynamic performance of the car as this would create drag and potentially causeflowseparation. The flow of these layers of air over an object can be described as beingeither laminar or turbulent. A laminar flowis theideal situation,with the streamlines flowing parallel to each other in a neat and organised fashion.A Laminar flowis desired over the top surfaceof a Formula One car as it will invariably occur ata low velocity,meaning that the air flowon the undersidewill be of the desired higher velocity.A Laminar flowis also far easier to analyseas itwill beeasier to predict and visualize. A turbulent flowwill occur when the layers of air become disturbed and start to flow in different directions.A Turbulent flow can be caused by factors such as the weather, or by the design of the car itself.A turbulent air flowwill usually occur in a situation of high velocity, so can often be found on the undersideof a Formula One car where the air is accelerated. Figure2.2 shows the several layers of air flowingover an object, and also indicates differences between laminar and turbulentflow that is created as a resultof the objects shape. Determining whether a streamlineis turbulent or laminar is importantto the design of a Formula One car as the different forms of flow have dramatically differentproperties when it comes to the issues of drag and flowseparation. Whether a streamlineis laminaror turbulentcan be determined through its Reynolds Number. A Reynolds Number is the ratio between the viscous forces actingon,and the forces contributingto the velocity,of a flow of air.A low Reynolds Numbers would indicatea streamlinewhere the viscous forces aredominant, with the opposite true for a high Reynolds Number. The Reynolds Number in relation to the air flowingover a Formula One car can be calculated through the followingequation: 𝑅𝑒 = 𝜌𝑉𝐿 𝜇 𝜌 = 𝐴𝑖𝑟 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 𝑉 = 𝐴𝑖𝑟 𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝐿 = 𝐶𝑎𝑟 𝐿𝑒𝑛𝑔𝑡ℎ 𝜇 = 𝐴𝑖𝑟 𝑉𝑖𝑠𝑐𝑜𝑠𝑖𝑡𝑦 If the resultof the above equation in relation to a flow was to resultin a Reynolds Number of less than 2000,then the flowcan be termed as laminar.Therefore if this number is greater than 2000 then the flow would be turbulent.
  8. 8. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 7 | P a g e 2.3 Drag Any object that is subjectto the flow of air will createa certain amount of drag that will work against the motion of that object. Drag is one of two forces, the other being pressure,that are produced as a result of aerodynamics.The force in question here is the shear force that acts in parallel to the surfaceof the objects body. The shear force created only works towards creatingdrag, and has no effect on the downforce produced. As a result the design of any aerodynamic objectwill be geared towards minimalizingtheamount of dragproduced. There are several different types of drag,the impact of which can all bedetermined through use of what is termed the dragequation: 𝐹𝐷 = 1 2 𝜌𝑣2 𝐶 𝐷 𝐴 𝜌 = 𝐹𝑙𝑢𝑖𝑑 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 𝑣 = 𝑂𝑏𝑗𝑒𝑐𝑡 𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝐶 𝐷 = 𝐷𝑟𝑎𝑔 𝐶𝑜𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑡 𝐴 = 𝐴𝑟𝑒𝑎 𝑜𝑓 𝑂𝑏𝑗𝑒𝑐𝑡 𝐶𝑟𝑜𝑠𝑠 𝑆𝑒𝑐𝑡𝑖𝑜𝑛 Any object of any shape possesses a certain dragcoefficient,as shown in figure 2.3, with the higher the number the greater the force of drag will be. The dragcoefficientof an object can be calculated fromthe followingequation: 𝐶 𝑝 = 2𝐹𝐷 𝜌𝑣2 𝐴 𝐹𝐷 = 𝐷𝑟𝑎𝑔 𝐹𝑜𝑟𝑐𝑒 𝜌 = 𝐹𝑙𝑢𝑖𝑑 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 𝑣 = 𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑜𝑏𝑗𝑒𝑐𝑡 𝐴 = 𝐴𝑟𝑒𝑎 𝑜𝑓 𝑜𝑏𝑗𝑒𝑐𝑡 Most modern cars,and more specifically racecars,will havea dragcoefficientof less than one; with a Formula One car varyingbetween roughly 0.75 and 1.45 depending on its aerodynamic set up. It is important to note that a Formula One car will possessquitea high coefficientof drag as a consequence of firstly the rules that stipulatethat they must be of an open wheeled and cockpitdesign which themselves create drag, and the fact that the design of a Formula One car is centred on producingdownforce, which will always resultin drag being produced as a sideeffect. Therefore the design of a modern Formula One car is a compromisebetween downforce and drag. It is for this reason that many objects subjected to motion have a slick and streamlined design, seeingas this shapeproduces less drag.The tear drop shapecan be seen to be ideal,creatinglittledrag as the shapehelps to prevent flow separation that would resultin drag. An object that possesses a drag coefficientof equal to one will besubjected to stagnation pressure.This is where the velocity of the air flow slows to zero, which,as Bernoulli’s equation tells us,means the static pressurewill equal thetotal pressure. These areas of stagnation pressure will poseas the areas where the maximum pressureis generated on an object, and will becommonly found on the leadingedge of a Formula One cars wing where the air flowis equally as likely to divertunder or over the wing. Figure 2.3 brighthubengineering.com
  9. 9. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 8 | P a g e 2.3.1 Viscosity An important factor that causes dragon an object is the viscosity of air.Viscosity isthe ‘stickiness’of a fluid and,although not immediately obvious,air is a viscousfluid.The greater the viscosity of a fluid the harder it becomes to push an object through it. Therefore itis this viscosity in theair that results in dragbeing created, as the ‘stickiness’works to push againstthe object moving through it. The viscosity of the air flowing over an object results in one of the fundamental concepts of aerodynamics forming,the boundary layer. 2.3.2 Boundary Layer As discussed earlier,the flowof air passingover an object consistof several thin layers or streamlines of air that areeither laminar or turbulent. One of these layers is known as the boundary layer which plays a significantrolein the aerodynamics of an object. The several layers of air flowingover an object do so at differingspeeds, with those closer to the object moving slower than those that are further away. Most of the layers move at what is known as free stream flow, where the velocity of the air is atits free stream value. The viscosity of the air causes thelayer closestto the object to slowto a velocity of zero, as the particles in the air ‘stick’to the object. The layers abovethis one closestto the surfacegradually increasein veloci ty,as the force of the viscosity of the surfaceair decreases,until the free stream speed is reached.This area of transition from the velocity of zero found at an objects surfaceto the velocity of the free stream layers is termed the boundary layer,and is represented in figure2.4. The Boundary layer plays a critical rolein the dragproduced by an object, and is therefore crucial in the design of a Formula One car. The thicker the boundary layer, the more viscous itbecomes, meaning that the thicker the boundary layer the greater the levels of dragproduced will be. Generally the boundary layer will startoutas a thin laminar flowatis origin,and gradually getthicker and more turbulent towards the rear of the car as the flowis disturbed This increasein thickness can lead to problems such as flow separation and resultin a significantincreasein dragcoupled with a loss of downforce. However the boundary layer thickness will decreaseas the air speed around the object increases,as the momentum of the free stream layers will be greater than the force created by the viscosity atthe object surface. Taking all this to hand we can see the importance of minimisingthe thickness of the boundary layer in the design of a Formula One car in an effort to reduce the levels of drag. However itmust be said thateven though there are many benefits to maintaininga prolonged laminar boundary layer in theform of dragreduction, a turbulent boundary layer can also bebeneficial to the performance of the car.A turbulent boundary layer can help to reattach any air flowthat has become separated, as the velocity of the non-parallel particles in the turbulent flow can help to reenergise the separated flow, helping to attract itback towards the car. 2.3.3 Skin Friction Drag There are three critical forms of dragthat Formula One designers must work againstin the design of their cars.The firstof these forces is skin friction drag.This is created as a result of the boundary layer that we mentioned previously. As we know the flowof the boundary layer over a Formula One car will startof in a laminar formand gradually changeto become turbulent. This change from a laminar flowto turbulent is known as the region of transition,and itis this turbulentarea of the boundary layer that causes what is known Figure 2.4 www.grc.nasa.gov
  10. 10. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 9 | P a g e as skin friction drag. The more turbulent the flow of air,the greater the viscosity of the boundary layer will be. This viscosity causes a friction between the air flowingover the car and the cars surface.This friction that develops creates a resistanceto the motion of the car,a resistancethat is of the form of drag.In order to reduce the impactof skin friction drag designers will aimto limitthe region of transition by makingthe car as streamlined as possible,allowingfor a more prolonged laminar flow,and limitingthe length of the car to the only the necessary length, as the further the air flows acrossa surfacethemore turbulent itwill become. 2.3.4 Form Drag The second type of dragthat Formula One designer must contend with is that of form drag. From drag is the resistancethe objects cross section surfacearea creates as itpasses through the air. The dragcoefficient of an object is directly related to the form drag that the object produces, with those of a lower dragcoefficient being ableto ‘slip’through the air with littleresistance. This issueof form dragis the reason as to why the front end of a Formula One car features few vertical flatfaces,as these would causedrag. Instead the front end features areas thathave very small crosssectional areas. The impactof form dragwill be largely dependent on whether the air flowis laminar or turbulentas it passes over a particular area of the car. The flow of air will always look to stay attached to an object, as is the casewith a laminar flow,and the shape of an object will determine whether the air stays attached or if flow separation will occur.Flowseparation will resultin an increasein drag.As stated earlier the tear drop shape has been found to be the ideal shape for reducingdrag, as the rounded front and narrow rear help to keep the air flowfirmly attached. This tear drop shape can be found on a Formula One car,startingatin the middle section where the sidepods begin, and then gradually movingtowards the rear as the cars bodywork becomes narrower, resemblinga coke bottle. This shapehelps to keep the air flowingaround the sideof the car attached, reducing drag. 2.3.5 Induced Drag The third significantformof drag that causes resistanceto the motion of a Formula One car is thatof induced drag. Induced dragis the resistancethatis created from the aerodynamic components of the car that work to produce downforce. For this reason we can see why itis termed ‘induced’ as itis caused by objects placed there by the designers as opposed to being a consequence of the natural shapeof the car. Induced drag is an unavoidablesideeffect of any aerodynamic device on a Formula One car that works to produce downforce. For this reason designers will look to find a balancebetween the induced dragcaused by a n aerodynamic feature and the downforce that itcreates. The impactof induced drag will bedependent on the levels of attack that a wing is set up to, with the higher the angle the greater the downforce and drag. The higher the angleof the wing the greater the pressuredifference between the upper and lower surfacewill be, meaning more downforce is produced,however this higher angle will also causemore turbulent vortices to be created at the wing tips.These vortices create dragand limitthe straightlinespeed of the car.It is for this reason that we see aerodynamic set up changes from circuitto circuit,as on tracks thatfeature longstraights the wings will be adjusted to run at a flatter angle, meaning less dragis created. Figure 2.5 Showing the reasons we see frictional and form drag people.oregonstate.edu
  11. 11. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 10 | P a g e 2.4 Lift/Downforce The main aimof the aerodynamics of a Formula One car is to produce downforce. As we learned from Bernoulli’s equation,downforce is created from the pressuredifferences of the flow of air runningover and under an object. Downforce is the term given to negative lift,and is achieved through the use of the basic aerofoil shape,run in an inverted fashion as to placethe longchord of the foil facingdownwards.This orientation of the aerofoil works to force the air runningon the undersideto accelerate as to maintain the velocity and stay in stream with the air flowingover the top surface.This increasein speed causes the pressure to drop, resultingin the air flowabove the aerofoil beingattracted to the high pressurezone on the top surface,pushingthe aerofoil to the ground; this phenomenon can be seen in figure 2.6 Of coursenot all aerodynamic devices areof this sameshape; however they do all work to the same principleof acceleratingtheair flowrunningon the underside. As stated earlier downforce is always a compromise between the force created by the downforce and that caused by drag.As we will discover later in the project, designers over the years have found various ways of producingdownforce in the design of a Formula One car. The three main methods of producingdownforce arein the use of wings that will be run at certain levels of attack as to acceleratethe air faster,the overall shapeof the cars body and through the use of a venturi system that will work to accelerate the flowof air runningthrough it. We will look further into these methods later on. The optimum flow form for downforce to be produced is laminar;therefore many aerodynamics devices are designed to keep the flow of air laminar as to allowother devices to work more efficiently.Flow separation thatcan be caused by a turbulent flowover the upper surfacecan lead to a lack of downforce, so designers will look to iron this issueoutin the design of their cars. The amount of downforce produce by an object is again dependent on various factors likeair density and velocity. However there are two particular coefficients thathave a major bearingon the levels of downforce produced. Firstly the pressurecoefficients of the various points on an objectwill determine its effectiveness at producingdownforce in the firstplace,as fromthis coefficient we can see and map the areas of high and low pressureon an objects surfaceand throughout the entire flow of air,aidingin thedesign. The pressurecoefficientof an object can be determined from the followingequations,which one is used is dependent on the surrounding environment and specifically thespeed of the air flowand whether it is compressibleor not: 𝐶 𝑃 = 1 − ( 𝑉 𝑉∞ ) 2 𝐶 𝑃 = 𝑝 − 𝑝∞ ( 1 2 ) 𝑝𝑉∞ 2 𝑝 = 𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑎𝑡 𝑔𝑖𝑣𝑒𝑛 𝑝𝑜𝑖𝑛𝑡 𝑉 = 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝑜𝑓 𝑓𝑙𝑢𝑖𝑑 Figure 2.6 www.diracdelta.co.uk
  12. 12. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 11 | P a g e This pressurecoefficientcan be used to identify areas of high pressure on a Formula One car, meaning the design can be analysed as to determine whether an aerodynamic device is workingas intended. The second coefficientthat has a bearing on the downforce produced by an object is its coefficientof lift.Similarly to a dragcoefficient, the liftcoefficientof an object determines how effective its shapeis at producinglift.Related to a Formula One car,a negative liftcoefficientis desired as to produce negative lift,or downforce. The liftcoefficientof an object is required to calculatethe total liftforce that it is ableto produce, however likea dragcoefficientthis number is usually a known value and acts as a constantin the liftforce equation. To calculatethe liftcoefficientof an object the followingequation is used: 𝐶 𝐿 = 𝐿 1 2 𝜌𝑉∞ 2 𝐴 𝜌 = 𝐹𝑙𝑢𝑖𝑑 𝐷𝑒𝑛𝑠𝑖𝑡𝑦 𝐴 = 𝑂𝑏𝑗𝑒𝑐𝑡 𝐴𝑟𝑒𝑎 𝑉 = 𝐴𝑖𝑟 𝐹𝑙𝑜𝑤 𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 𝐿 = 𝐿𝑖𝑓𝑡 𝐹𝑜𝑟𝑐𝑒 Finally to calculatethe liftforceof an object or in relation to a Formula One car the negative liftforce, the followingequation is used. 𝐿 𝐹 = 𝐶 𝐿 1 2 𝜌𝑉2 𝐴 The liftcoefficienttakes into account the effect of the shapeof the object relevant to the formula has on the air properties of the flow stream, with the area the being reference planeupon which the total valueof the change in pressureis found. Obviously any resultfromthe above equation that is a negative number will produce downforce as opposed to lift,so we can see how the equation is relevantto Formula One. 2.4.1 Coanda Effect The Coanda effect is an important phenomenon within the aerodynamic principles and is thebasis of how downforce is produced by a Formula One wing. The Coanda effect states that a flowof fluid,likethe air flowingover a Formula One car,is likely to become attached to a surfacein closeproximity,as shown in figure 2.7. It is this principlethatallows us to understand why the many layers of air travelling over a Formula One car will remain attached to its surface rather than simply continue in a straightline.The air flowwill followthe route of the surfaceand realign with the free stream flowupon passingthesurface. The Coanda effect is especially prevalent on curved surfaces such as an aerofoil,where the flowof air will look to followthe curvature of the surface.This phenomenon has allowed designers to experiment with varyingshapes and angles of attack with their wing designs, as the coanda effect will allowfor the flowto travel over the upper and bottom surfaces of the wing, creatingthe pressuredifference required for downforce to be produced. 2.5 Slipstream/Wake We could not finish this chapter on the basics of aerodynamic theory without lookingatthe reasons for and effect of an objects wake as itpasses through air.The wake that is generated by an object that moves through air also has a bearingon the aerodynamics of that object itself,as the extra energy required to carry this wake in its trail will contributeto the drag of the object. However the wake generated by an object will Figure 2.7 formula1-dictionary.net
  13. 13. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 12 | P a g e have a far greater impact on anythingfollowingbehind. When the object in question is a Formula One car,the wake that is generated is generally referred to by the terms ‘slipstream’or ‘dirty air’. The wake that is generated by a Formula One car can be both beneficial and detrimental to the aerodynamic performance of any rival cars followingclosely behind,roughly up to 10 to 20 car lengths depending on set up. The strength and reach of an objects wake is largely depended on the form dragof the object, with more streamlined and slippery shapes havinga far smaller wake,as shown in figure 2.8. This is because the wake of an object consists of the turbulent air that is generated as the air flowbecomes separated from an object towards the rear, and then when complete flow separation occurs asitdrops of the end of the objects surface.This turbulent flow continues to circulateafter the object has moved on, leavinga track of ‘dirty air’behind the object. Any car that then passes through this turbulent area will suffer froma lack of downforce that will lead to issues such as understeer, as itwill notbe ableto gain the advantages of the laminar flowthatit would encounter in an undisturbed flow. As well as the turbulent flow that follows in the track of an object, aerodynamic devices likewings will create vortices at their tips as the air passes over them, as seen in figure 2.9. These vortices will contributeto the ‘dirty air’generated by a Formula One car. A car followingin the wake of another can gain an advantage by usinga technique known as slipstreaming,or drafting,in order to gain an increasein straightlinespeed.The turbulent air leftin the trail of a passingFormula Onecar will continueto travel in the direction of the car,rather than remain static, and therefore will travel ata similarvelocity.This will result in a continuous separated flowbehind a Formula One car,meaning that the car will effectively be ‘punching’ a hole in the air as itpasses through it.This ‘hole’ will be moving at the same velocity of the leadingcar and will therefore create a zone of reduced atmospheric drag behind the leadingcar,meaningthat any car followingin this zone will suffer from far less resistanceas a resultof drag, and will therefore be able to achieve a higher top speed. Figure 2.8 howthingsfly.si.edu Figure 2.9 asracingblog.com
  14. 14. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 13 | P a g e 3. History ofFormulaOne Design Before any discussion into the aerodynamic design of the modern F1 car and the tools which are used in its design,it would be best to firstly look briefly into the history of the design of the cars that we have seen in the pastand how they have evolved from the primitivedesign of the 1950s, to the precisefeats of aerodynamic engineering that we see on today’s F1 cars,that are in essence an upsidedown aeroplane,with many of the advancements in technology and design taken directly from the aerospaceindustry itself. 3.1 The Early Days The Formula One world championship as weknow ittoday was conceived in the year 1950,with a variety of the top car manufactures across Europe,alongwith several independents, competing with the sole aimof winning. With the conception of the Formula One world championship,so with itcame the birth of the Formula One car itself.During the early days there was a notabledifference in the design theory behind the cars which made up the grid,due to the somewhat lax regulations thatwere enforced at the time and the substantial differences in budget. Despite this most of the cars typically followed the same core design philosophy, comprisingof front mounted engine, narrowtyres and basic drumbrakes.This primitivedesign was a resultof littleevolution into the design of singleseatrace cars beingmade over the previous fifteen years,due mainly as a consequenceof WWII.The lack of evolution is bestobserved by the factthat the leadingcar of the firstfew years,the Alfa Romeo 158,was developed way back in 1938. The 158 offers a good example of the design of these early grand prix cars,as littlethought was given to the aerodynamic efficiency of the car,in fact the main cooling system employed by teams at the time consisted simply of a radiator and air intakebeingplaceatthe nose of the vehicle, causinga seriousobstruction to the aerodynamic s of the car.These cars were builtpurely for speed, with the littleaerodynamic knowledge that was factored into the design of the Formula One car being centred on streamliningthe bodywork for greater a top speed. The arrival of Mercedes-Benz to the series brought about a greater level of professionalismto the sport. With their all-conquering W196 which pioneered the use of several new technologies in the sport such as fuel injection and was the firstto put greater focus on the ‘streamlining’of the bodywork. This forced the other competitors to up their game, and most importantly deviate away from the traditional design of grand prix cars thathad been used for the pastfew decades. The firstsignificantchangein design that led to the cars we see today was the relocation of the engine block from the front to the middleof the vehicle,with the engine mounted behind the driver.This design theory was introduced to the sport by Cooper in 1955, havingbeen initially pioneered by Auto Union way back in the 1930s.This design method proved far more beneficial than its front engine counterpart, becoming the standard before the decade was out. The transition fromfront-engine to mid-engine brought with it far greater handlingcharacteristics and opened the minds of engineers of the time to pursue design ideas that would lead to greater corneringspeeds, as opposed to straight-line. 3.2 Safety and Chassis Design Revolution This pursuitof corneringgrip swiftly brought an end to the somewhat ancient, and dangerous, useof drum brakes, which if nothing showed how littlethought was given firstly to driver safety and to anything other than straight-linespeed in the initial years.Theintroduction of the mid-engine racecars broughtabout the use of the disc brakes,still widely used to this day, as a means of stoppingthe car. It was around this time that driver safety was firstcontemplated when the cars of the day were being designed. The year 1960 marked the introduction of the firstsafety regulations beingenforced by the governing body. These forced designers to introducefeatures such as roll-over bars into the design of their racecars, resultingin significantvisual changes to the design of the Formula One cars of the day and bringingthem more in linewith the present day.
  15. 15. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 14 | P a g e The implementation of safety features and the change in brakingsystem itself lead to dramatic improvements being made in car design and lap times over the next couple of years,however itwould not have such a significantimpactthatthe next innovation in design would make on future grand prix cars. 1962 brought about the introduction of the monocoque construction that would lead to a revolution in the chassis design of all subsequentFormula One cars up and down the grid.The switch from the traditional tubelike frame to the monocoque method allowed engineers to placethe drivers in a position far more reminiscentto the situation thatwe see today where they arebasically lyingon their backs.This shiftin chassis design allowed for far more aggressivedesigns to be used in the pursuitof lowering lap-times,seeingas the driver was now far less of an obstruction. The monocoque construction allowed for far stronger chassis beingdesigned. This lead to the introduction of grand prix cars thatwere visibly ran atfar lower rideheights and had a significantly narrower and lighter chassis. This step in Formula One car design opened the road for the introduction of an innovation that led to the cars resembling the ones that we see today. One of the most significantevolutions in thedesign of the Formula One car was the introduction of the Ford Cosworth DFV engine. The Ford Cosworth DFV brought about a revolution in Formula One engine design that still stands truetoday. The DFV engine was initially introduced in the year 1967 and proved to be staggeringly successful in comparison to many of the flat-12 engine configurations thatwere being employed by teams such as Ferrari atthe time, winningover two thirds of the races that it competed in. However rather than the engine itself beinga significantevolution in Formula One car design,it was the manner in which it was mounted that did. Colin Chapman introduced the concept of usingthe engine as a stress bearing unit, or structural member, effectively makingit a partof the chassis fromwhich other components such as the rear suspension could beattached. This design theory quickly became the norm and is still widely accepted as the ideal method of attachingthe engine to the monocoque. 3.3 Aerodynamics Arrive The aerodynamic wings that we see on the modern Formula One car havebecome synonymous with the sport, and it was towards the end of the 1960s that we sawthe initial foray into the useof aerodynamic wings to providedownforce. The lowering of the chassis allowed for greater emphasis to be placed on the aerodynamics of the vehicleas a whole and itwas duringthe 1968 season that the firstfrontand rear wings began to crop up among the field. The use of front and rear wings in the sportto produce downforce was instigated by designers taking knowledge from the way in which the aviation industry employed wings into their aircraftdesign to produce flight,and applyingthis to the design of the Formula One car,only in the reverse manner to produce downforce. Designers faced initial difficulty in getting the concept to work, with many attachingbizarrelooking struts to the front and rear of their cars thatwere eventually banned due to safety concerns.However by the end of the decade front and rear wings were being employed throughout the grid to great effect, and were fixed directly to the chassis itself. Over the next few seasons the research into the use of wings and other aerodynamic innovations to produce downforce ballooned,with designers eager to extract maximum potential from this new found gold mine that was aerodynamics. This flurry of activity led to an array of differingconcepts,such as the Hesketh front-front wing, being trialled up and down the grid, many of which led to the creation of hideous and downright stupid lookingcars beingdeveloped by teams. 3.4 Pushing Design to the Limit It was not the use of wings as an aerodynamic benefit that would have the greatest impacton the performance and design direction of the Formula One car over the next decade. The Lotus 78 that was introduced in the 1977 season was the firstin a succession of cars thatemployed the use of ‘ground effect’ as
  16. 16. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 15 | P a g e a means of producingfar greater levels of downforce than was previously possible. The introduction engine design concept used by the Ford Cosworth DFV that was firstused over a decade beforehand led to the possibility of ground effects as an aerodynamic tool. This was largely dueto the V configuration thatthe DFV engine ran to. This factor was critical in theapplication of ground effect to the cars atthe time, due to the fact that the V shapeof the engine left plenty of spaceat the under body of the car,allowingteams to produce the ‘Venturi Effect’ with the design of the undersideof the vehicle. The use of ground effects transformed the Formula One race car from a chassiswith wings attached; to what in itself was a whole wing ran upsidedown. The ‘Wing Cars’as they came to be known employed the rules stated in the Bernoulli’s Principleto significantly improvethe levels of grip which they were ableto produce. This led to massiveimprovements in performance being found and lap times tumbling, becoming more likethe times that we see today. Formula One car design pushed the theory of the ground effect car to its very limit,creating dangerously quick machines for the time. One innovation that brought great increases in performancewas the introduction of flexibleskirts thatran atthe bottom edge of each sideof the car.These skirts formed a seal between the under body of the car and the outer body aerodynamics,massively increasingthepotential of ground effects. Another example of teams pushingthe theory of ground effects to the limitwas seen in the BrabhamBT46 fan car,that employed the use of a huge fan placed atthe rear of the vehiclewith the aimof greatly reducingthe pressureof the air flowingon the under body of the car.The fan car only raced once, a racewhich itwon, before it was quickly banned. This push in the development led to many drivers losingtheir lifeas a resultof safety essentially beingpushed to the sidein the attempt to ascertain the greatest levels of performance from these ‘WingCars’.It was for this reason the FIA decided to ban the concept in the early 1980s,meaning its full potential was never truly unlocked, forcingdesigners to pursue other avenues in the quest for downforce. 3.5 Turbo Era The Ford Cosworth DFV remained the engine of choicefor most of the field up until the next major step up in Formula One car design,more specifically enginedesign,was to appear in the sport towards the end of the 1970s. In 1977 Renault entered the sport, pioneering their 1.5L V6 Turbocharged engine, placingitin direct competition againstthe all-conqueringDFV.Despite early troubles the Renaulthad become a proven race winner by the year 1979,forcingother teams to take note and rethink their ideas.As the technology behind the Formula One turbocharged engine progressed at a rate of knots the sportmoved forward into the 1980s, the potential of the engine became apparent. As the use of turbos became more refined, allowingincreasing amounts of power to be unlocked, the power disparities between the naturally aspirated and turbo charged engines became more and more evident, with vastly superior horsepower levels beingpossiblewhilstutilising the turbo engine. This factor,alongwith the banningof ground effects due to safety concerns,led to the transition of the majority of the grid moving towards turbo power by the beginningof the 1984 season. The reason for this was the reintroduction of huge front and rear wings, that had largely disappeared duringthe previous era when the cars were basically onesinglewing,that was brought about as a means to make up for the loss of downforce that occurred as a resultof ground effects being banned. These larger wings,although generating great levels of downforce, also created a lotof drag that hindered the cars top speed. Therefore the use of the turbo engines greater power enabled teams to clawback this loss in speed through engine power, making the transition fromnaturally aspirated to turbo-charged a near necessity. The turbo era lasted for the next few seasons,with some quite staggering pieces of engineering produced towards the end. The final year of the turbocharged Formula One Car sawwitness to cars capableof
  17. 17. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 16 | P a g e producingnear 1200BHP, leadingto speeds that were previously unthought-of in the sport. The ever increasingpower of the cars atthis time led to several revolutions of Formula One car being seen over this era, with the cars becomingfar wider and chunkier to accommodate the powerful engine. This fact also sawthe introduction of incredibly widerear tyres as means of allowingthe car to lay down its power, creatingthe definingimage of F1 car that many envisage for the turbo era.This increasein speed and the rising costof the turbocharged engine forced the FIA to ban the concept in the year 1987, forcingteams to move back to the naturally aspirated engines that had been used previously. This reversion led to far slimmer and streamlined Formula One cars beingdeveloped throughout the grid,once again placingtheemphasis on the aerodynamics of the car as opposed to the power. This led to Formula One car design becoming far more similarto what we see atpresent. 3.6 Modern Day The modern day Formula One car is in many ways the pinnacleof the design theory that was introduced as a resultof the banningof turbos, with a few minor changes being mandatory due to safety issues thatcropped up over the lastdecade or two. With designers minds around this time firmly centred on improvingthe handlingof their cars,a shiftin the materials used to construct the various components of a F1 car occurred duringthis period, with teams startingto use the ultra-lightmaterial of carbon fibrefor the first time. Initially theuse of carbon fibrewas pioneered by McLaren, who used the material in the construction of the monocoque for their highly successful MP4/1.Over the next decade the use of carbon fibrebecame widespread, with teams utilisingthematerial in the construction of key components such as the suspension wishbones,chassisdesign,exhaustsystems,diffuser and the entire bodywork of the car to produce far lighter breed of Formula One car. The word safety has essentially been the definingreason cars look likethey do today. The banningof turbos led to far greater thought being given to the aerodynamics design of the car.This l ed to incredibly refined aerodynamic features, such as multi decked front wings, barge boards,sculpted sidepods among others, croppingup over the next few years. The risein electronic driver aids becameapparent at the beginningof the 1990s,with many innovations thatwe see in road vehicles today,such as traction control and activesuspension,being developed in Formula One atthis time. Most of these aids were banned by the year 1994,a significantyear in the history of Formula One car design.The death of Aytron Senna at the San Marino GP in 1994 forced the FIA to look into the safety concerns that were present in the F1 cars of the time. This led to many design features, such as higher cockpits which extend half way up the drivers head as to provide greater protection, that we see today becoming mandatory. The next few years of car design were generally focused on slowingthe drivers down and creatingfar safer vehicles.There was however still roomfor the creative minds to introduce a few interesting innovations and concepts to the sportin the search of greater levels of downforce. This created a Formula One car that looked somewhat a mess towards the end of 2008, with several aerodynamic features croppingup all over the bodywork. This led to what is known as ‘dirty air’becoming a serious issuein the sport. The greater levels of downforce that the cars were producingcreated far higher levels of turbulence in their wake than was previously seen in the sport, making overtakingdifficult.This factor lead to the rules changes that we saw introduced in 2009 come into effect. The 2009 rules changes transformed the Formula One cars into those we see today, far more streamlined and tidy vehicles,with a greater emphasis on the sculptingof the body work, particularly atthe rear, and featuring wider front wings and taller rear ones. This set of rulechanges also sawthe introduction of KERs into the design of the Formula One car,a critical componentlookingto the future.
  18. 18. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 17 | P a g e 4. The FormulaOne Car So as we discussed over the courseof the previous chapter, the Formula One car as a whole is the resultof many decades worth of research and development centred on creatingthe quickestcar that meets the rules and regulations of the time. During this chapter we will look atthe various features that comprisethe aerodynamic packageof the Formula One car that we see today, detailingthe several keys design areas of the vehiclethat make it the pinnacleof motorsport. 4.1 Makeup of an F1 Car Before lookingat the aerodynamic packagein greater detail,itwould be best to identify the basic makeup of a Formula One car as a whole. The Formula One car is,as italways has been,an open wheeled and cockpit,singleseatrace car.This means that the drivers head is always in theopen and the suspension arms among other components are clearly visibleexternally. Theoverall design of Formula One car is governed by the rules and regulations setout by the FIA. This means that although the Formula One car is seen by most as the pinnacleof the automotive industry,itis by no means the true representation of the limitof automotive performance. In fact due to several technological advances thathave appeared in the world of Formula One over the years being banned, the makeup of the cars thatwe see today is relatively simplecompared to what would be possibleif there were no rules. When thought of from the barebasics theFormula One car as a whole can be broken into three key sections.The firstbeingthe front structureof the vehicle,here we find the front wing, nose cone and front suspension system.The design of the front section is critical when determining the aerodynamic properties of the car,as the manner in which the air is ableto flow over this area of the car will dictatethe flow over several other areas of the car.The middle section of the Formula One car is very much the heart of the operation, not leastbecausethis is where the driver will beplaced. In this area we find the chassisof the vehiclein which the cockpitand survival cell areplaced.Directly behind this the engine is found which is encased in the engine cover featuring an air box at the tip. The fuel tank is located atthe bottom end of the chassis. All these features are tightly packed in-between two sidepods either sideof the car which again arecritical to the aerodynamics and coolingof the vehicle. The rear section of the Formula One is generally the area which generates the greatest levels of downforce and is vital in ensuringthatthe car remains ‘planted’to the ground. Along with the rear wing, the back section of the car also houses the rear suspension systemand diffuser beneath. The diffuser is crucial to the cars aerodynamic performance,and has in recent years been the subjectof much controversy.Finally a floor is located beneath the car that is heavily regulated to ensure that itremains flat,a rule that is necessary as a consequence of the banningof ground effects. A Formula One cars performancewill be dependent on all these different sections of the car working together as a complete package, with the design rarely beingas simpleas simply strappingonegood design feature to a poor car in the hope findingperformance. Having detailed the extremely basic makeup of a Formula One car we can now delve into several of these key design aspects of the aerodynamic packageof the car that contributes massively to the performance of the car.Form here we can look into the principles behind each one, and see how they work in conjunction with each other to create the ‘complete package’. 4.2 Aerodynamic Package Enzo Ferrari oncesaid “Aerodynamics are for people who can’t build engines.” How wrong he has been proven to be as the aerodynamics of a Formula One car is the singlemost important area that the designers will need to consider.As discussed earlier theaerodynamics features of a Formula One car have come a long way over the courseof the lastfifty years or so, featuringmany different aerodynamic devices.
  19. 19. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 18 | P a g e The crucial rolethataerodynamics in producingthe greatest levels of performance can be best explained in the recent quote by former F1 engineer Gary Anderson, who said “It's the aerodynamic side that gives you lap time. The mechanical side, generally, only lets you down. It loses races; the aerodynamic package is what wins races”.1Taking this factor to hand the design of a Formula One car will becentred on the aerodynamic performance of the car,with all features of the design builtto work in conjunction with the aerodynamic package,not the other way round. In order to design to the optimum aerodynamic packagefor the car,designers will befaced with the task of finding the correct balanceas to ensure that the maximum levels of downforce are created whilst producingminimal amounts of drag. The aerodynamic packageof the Formula One car will generally be designed from front to back. This is dueto the fact that I mentioned earlier which stated that the car must perform as a package, not as several individual parts.Takingthis into accountthe under body of the car will need to be designed to deal with the specific air flowthatis generated from the front wing, with the rear wing utilised to create further downforce from the up wash generated by the floor for example. The two key aerodynamic features present on a Formula One car are the two wings and the under body, that consistof the floor and diffuser,which contribute towards the majority of the downforce produced. This is notto say that they are the only areas given thought, in fact every single exterior component and surfaceof the F1 car will be sculpted for optimum aerodynamic performance. There areseveral key features of the aerodynamic design of the Formula One car,each of which has a major impacton the performance of the car as a complete package. 4.2.1 Front/Rear Wings The front and rear wings have become synonymous with the modern day Formula One car and are visibly the most immediately obvious aerodynamic feature of the vehicle. Due to the present day regulations banningground effect; the wings of a Formula One car are the areas fromwhich the greatest levels of downforce aregenerated. It is estimated that 60% of the downforce that a Formula One car generates is as a resultof its front and rear wings. Front Wing The front wing is considered by some to be the singlemost important feature of a Formula One cars design in terms of contributingto the overall aerodynamic performanceof the vehicle.The reason for the front wing being of such importance to the design of the car as a whole is due to the factthat it is the firstpart of the car that comes into contact with the air around itself. As a consequence of the front wing preceding all other components of a Formula One car design, it will dictatethe manner in which the air will flowover all other parts of the car seeingas they will bein the wake of the air thathas been worked by the wing. As a resultof this the design of the front wing will havea huge impacton the aerodynamic efficiency of the car as a whole. On its own the front wingproduces roughly a third of the overall downforceof a Formula One car , with some producingas much as 500kg of downforce, meaning that it is the area in which teams will generally look towards in the hope of improvingperformance. However this performance gain isn’talways acquired through increasingthe amount of downforce generated by the front wing, with many teams needing to make compromises on the design of their front wing as a singlecomponent so to improve the flow of air over the rest of the car.This fact is clearly evidentin the front wing designs that we see on the grid today, with many teams’ showcases incredibly complex lookingsolutions,many of which consistof three or more elements, with the aimof optimizingthe flow of air that travels over the rest of the car. In fact a simpler design of two elements would yield higher levels of downforce, but with the downsideof impedingthe air flowover the rest of the car,a clear indication thatthe design of a front wing is far from simply centred on generating the greatest amount of downforce. These intricatemodern day designs area resultof thousands of man hours 1http://www.bbc.co.uk/sport/0/formula1/20844843
  20. 20. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 19 | P a g e being put into analysingevery aspectof a front wings design,this vastresearch leadingto the incredibly complex solutions thatwe see on the grid today, which is a far cry from the singleplanewings that we saw initially used in the sport. The general construction of the front wings that we see today consists of a main planewhich on its own acts as an aerofoil.Upon the main plane several layers of flaps areplaced,the amount of which is dependent on the desired downforce levels.At each sideof the main planean end plate is found.The end plate plays a crucial rolein the aerodynamic efficiency of the Formula One car as a whole, its firstjob being to keep the flow of air over the front wing confined within the main planeand over the flaps,preventing any air from spillingover the sides.As well providingcontrol of the air flowover the front wing itself,the end plates are also designed as to force the flowof any turbulent air away from the car,preventing it from disrupti ngthe aerodynamic performance of other areas such as the diffuser. So from a design point of view the front wing is the most critical aerodynamic featureof the car, havinga huge bearingon the overall performance of the car.Figure 4.1 demonstrates this,showingthe effect that the front wing has on the air flowand how it is used to simultaneously producedownforce and optimise the air flowfor the rest of the car. Another importantfactor to consider is thatgenerally speakingthe regulations regardingthe design of a front wing are quite relaxed in comparison to other areas of a Formula One car, leavingroomfor designers to be far more creative in their thinking,another reason as to why itis so crucial. Rear Wing As a singleaerodynamic component the rear wing of a Formula One car can generate more downforce than any other area of the car.Red Bull claimthattheir rear wing ran at its highestdownforce setting is capableof producingin excess of 1000kgof downforce; doublethat of the front wing. However as a resultof the rear wing being placed atthe very rear of a Formula One car,it doesn’t have quite the same bearingon the overall aerodynamic package,and can be seen more as an individual component. This isn’tto say that the design of the rear wing will beperformed independently from that of other features of the cars aerodynamic package,as the rear wing will still need to be optimised to work as efficiently with the flow of air that is produced by the preceding aerodynamic features on a Formula One car. Rear wing design has been fairly basic in comparison to that of the front wing over the years ,with regulations in placeto limitthe number of elements present on a Formula One cars rear wingto two. The two elements of a rear wing are crucial to the design as the slotthat is created as a result helps to speed up the flow of air runningon the undersideof the wing, preventing the wing from stalling.If the rear wing were to stall a dramatic lossof downforce would occur, potentially causingthedriver to losecomplete control of the car. The principlein which the rear wing is ableto produce downforce is achieved through the shapeof the wing, which is designed to create a situation where the air flowingunderneath the wing is accelerated to a greater velocity than that which is travellingover the top. This creates a difference in pressure,with the air flowingunder the winglower than that over the top, which results in the wing being forced into the ground. Aside from the two element wing placed at the top of the rear wing structure, the use of a beam wing located lower down the structure justabove the diffuser also helps to generate downforce and keep the flow of air over the car atan optimum. Figure 4.1 sidepodcast.com
  21. 21. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 20 | P a g e From a set up point of view the angle the rear wing can be adjusted as to either increaseor decrease downforce, with the steeper the angleof the wing the greater the downforce will be,whilstalso producing more dragwhich will limittop speed. Like the front wing the rear wing is encompassed in-between two end plates that operate to improve the flowof air over the rear wingelements, as well as playinga crucial rolein the reduction of dragby limitingthe sizeof the vortices created at the wing tip,as shown in figure 4.2. Some teams run rear wing end plates that extend pastthe rear wing structure and continue towards the floor of the car,the purpose of which is to form an extension of the diffuser,another critical component in the aerodynamics of a Formula One car. 4.2.2 Floor and Diffuser After the front and rear wing, the floor and subsequent diffuser of a Formula One car are the next crucial aerodynamic features of the design. Although not immediately obvious to most, the floor plays a vital rolein the aerodynamic performance of the car.In fact in terms of individual aerodynamic efficiency the floor is the most effective component, producinghigh levels of downforce with littledragcreated as a result. Due to the banningof ground effects, the design of a Formula One cars floor is heavily restricted,with rules in placeto prevent the floor from being located below a certain point. This ruleis enforced via the use of a plank placed on the undersideof the floor, with the rules statingnothingmust protrude further down than this plank.This ruleobviously limits thepotential downforce that could be created from the floor as there would be a step in the floor as opposed to the desired flatfloor for optimum performance. The crucial role that the floor plays in the overall aerodynamic packageof the Formula One car is evident in the way that much of the design put into the front wing will beto optimize the flow of air under the floor of the car. The application of the floor of a Formula One car to produce downforce centres on replicatingthe venturi effect between the car and the surfaceof the track. As we know the venturi effect occurs in a situation when a constriction or throatis present in the path that the flow of air will follow.This constriction will cause the air to acceleratecreatinga pressure drop. This acceleration is seen in figure 4.3 where the greater velocity of the air flowunder the car can be seen in CFD. In terms of a Formula One car,the area between the floor and the surfaceof the track forms a constriction thatthe air flowingpastthe car must pastthrough. In this situation the front wing acts as the inlet to the venturi, directingthe air under the floor.As the air enters the constriction between the floor and the track,the pressuredrops from where it will reach the diffuser that will then take control of the air flow. Figure 4.3 racecar-engineering.com Figure 4.2 shell.com
  22. 22. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 21 | P a g e In the sameway that downforce is created by the rear wing, the lower pressureof the air running under the floor in relation to the air flowingover the body of the car will resultin downforce being generated. Essentially then the more the air flowingunder the floor can be accelerated, the greater the levels of downforce generated will be, hence the importance of the front wing design plays in directingthe air under the floor. One recent method teams have employed to increase this rate of acceleration is to run the cars ata considerablerake,so as to have a higher rideheight at the rear to that of the front. This has the effect of increasing theventuri that the floor will create. The floor of a Formula One car is sculpted as to work the air that flows from the front wing as effectively as possible.For this reason itis common to see what is known as a ‘tea tray’ protruding from the front end of the car under the nose, helpingto improve the flow of air under the floor. The floor as a singlecomponent will notgenerate downforce without working in relation with the front wing, diffuser and then finally the rear wing. The diffuser therefore plays a pivotal rolein the effectiveness of the floor and the aerodynamics of the car as a whole. The diffuser plays the roleof releasingthe accelerated air fromthe venturi that is created by the floor,and allowingitto return to its natural pressure.Takingthis into accountand knowing that the more the air underneath the floor can be accelerated,it is therefore clear that the quicker the air can be drawn from under the floor, the faster it will accelerate,in turn creatingmore downforce. The diffuser is constructed from carbon fibre to make itas lightas possible,consistingof an upwards curve with several strakes protrudingfrom this curve towards the track. These strakes play an importantrole in the way that the diffuser controls the flowof air atthe rear of a Formula One car,as they areplaced to ensure that the air is ableto leavethe venturi as smoothly as possible. The upwards curve of the diffuser acts to gradually increasethe gap between the tracks surfaceand the floor,allowingthe air to decelerate and return to normal pressure. The diffuser can contribute up to 30-40%of the total downforce generated by a Formula One car,and has for this reason been the subject of much design innovations over the pastfew season,which I will look into later in the project. The relation between the diffuser and floor is crucial to the overall balanceof a Formula One car as a small adjustmentto one can have a major impacton the performance of the other. Generally the downforce generated by the floor will contributetowards the front end grip of the car,with the diffuser heavil y focused on rear grip. Therefore the design of both components will need to be tailored to each other to ensure that they interact as efficiently with each other as possible.Takingthis into accountany design improvements made to the diffuser will need to be implemented to ensure that the floor is ableto acceleratethe air atan improved rate as well, maintainingthebalancein grip,as if there was to only be an increasein downforce generated by the diffuser,then only rear grip would be added, causingan imbalance. 4.2.3 Other areas The front and rear wing alongwith under body of a Formula One car generates the majority of the downforce that is produced, however there aremany other areas of the car that are designed with aerodynamics in mind,even if that is not their primary function. Chassis Design The chassiswill formthe basis of all Formula Onecars and although mostof its structure will be covered by bodywork, it is still notvoid of aerodynamic features aimed at improvingthe flow of air around and more specifically under the car.Many teams now sculptthe area of the chassisthatis visibleunderneath the driver,known as the keel, to optimize the flow of air that enters the under body of the car at the ‘tea tray’ section and progresses through the floor and onto the diffuser and rear wing. For this air to reach the floor it
  23. 23. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 22 | P a g e will obviously need to negotiate its way around the sides of the chassis.For this reason the keel is shaped,in most cases to a ‘V’ configuration to aid this flowof air pastthe chassis. Side pods The primary function of the sidepod is to act as a home for the engine coolingradiators,a concept that firstwas introduced by Colin Chapman with the revolutionary Lotus 72 that was the firstto use side mounted radiators.Clearly thesidepod poses as a significantobstacleto the flowof air over and around a Formula One car. For this reason the design of a sidepod has become ever the more refined over the years. Recently the trend of sidepod design has moved towards creating a very narrow rear end to the car.This has been termed the ‘coke bottle’ section as the sidepods can be seen to, in some designs,very aggressively curve inwards towards the rear. This ‘coke bottle’ helps to reduce the amount of dragcreated from the sidepods as well as help to optimize the flowof air over the rear tyres and onwards towards the rear wing. Modern sidepod design has also seen the introduction of a carefully sculpted undercut at the baseto improve the flow of air towards the rear end of the car,more specifically help to keep the air attached to the car and deliver it onto the diffuser. Some teams have also experimented with usingdifferent shapes of side pods, such as the McLaren MP4-26, which feature ‘L’ shapesidepods in the effort of improvingthe flowof air over the rear beam wing. This season has seen Sauber experiment with the use of an extremely narrowside pod design in the attempt to reduce drag,another example of the on-going research into the aerodynamic importance of the design of a sidepod. Barge Boards Barge boards and other appendages came to the forefront duringthe 2000s,with many different devices appearingon cars up and down the grid in the search of generating further downforce. Eventually these devices were seen to have extremely intricatedesigns,some lookingdecidedly ugly. In the effort to reduce the impactof turbulence air and aid overtakingthe use of these devices were severely restricted from the 2009 season onwards. As a resultof this the barge boards we see on the grid today arefar more basic and less effective than those a few years back. Despite this the barge boards on a Formula One car still play a significantrolein the overall aerodynamic package.The barge boards play the role of directingthe turbulent air caused by the front tyres away from the car,as well as helpingto keep the air flowfrom the front wing and ‘tea tray’ are attached to the car and direct the flowonwards towards the sidepods. Suspension Although clearly notan aerodynamic device primarily,dueto the open wheeled nature of a Formula One car the suspension arms presentin the suspension systemhave a significantimpacton the aerodynamics of the car as a whole. Although there is littleto no downforce produced by the arms themselves, it is important in there design to reduce the amount of drag that they produce. For this reason the design of modern day Formula One cars suspension wishbones has becomeever the more streamlined and ‘slippery’in the effort to ease the flow of air passingover and through them reducing the levels of drag. Another key design decision,from an aerodynamic pointof view, that will be necessary duringthe inception of a Formula One car is whether to use a pull rod or push rod suspension layout.The pros and cons of both is a separate topic, but for aerodynamic purposes the use of a pull rod layout can aid the aerodynamic properties of a Formula One car due to fact that the rod will notbe as much of an obstruction to the flow of air. This factor has seen the use of pull rod suspension re-emerge in the sport in recent years,startingwith the Ferrari F2012. Engine Cover The engine cover of a Formula One car obviously poses as a major aerodynamic dilemma in the design of a Formula One car.The shapeof the engine cover is generally directed by the engine, air box and gearbox
  24. 24. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 23 | P a g e sizeand location,as well as needingto meet the dimensions stated in the regulations.For this reason the design of the engine cover will be aimed at optimizingthe air flowover this part of the car and helpingto directit onwards towards the rear. Other than keeping the design as streamlined as possibleas to reduce drag, there is not any downforce generators located on the engine cover due to the regulations. Recent years sawthe use of what was known as a ‘shark fin’engine cover in the effort of reducing the cars yawsensitivity and improvingthe stability of the car under brakingand atthe rear end by creatingan easier path towards the rear wing for the flow of air to follow.However the FIA moved to effectively ban these ‘shark fins’for the 2011 season by introducinga rulethat designated an exclusion area in frontof the rear wing where no bodywork is allowed.
  25. 25. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 24 | P a g e 5. DesignProcess There are very few other engineering environments that feature the same challenges involved as that of the task of designinga Formula One racecar.To startwith the rules and regulations of the sport are in a constantstate of upheaval,with periods of relatively consistentsetof regulations regardingcar design a rarity. This obviously forces designers into constantly rethinkingtheir ideas in many cases,as quick as a genius innovation or design solution is born,itis then subsequently banned. As well as the changingregulations thatdesigners must contend with, the technology used both duringthe design process and actually on the cars themselves and tracksideis rapidly progressing,with Formula One being one of the most technologically advanced engineeringfields on the planet. Because of the great challengeinvolved in designingthe modern day Formula One car,the man power put to use has grown exponentially over the courseof the championshipsexistence.The days of a Formula One car design and construction beingcarried out by a small team, sometimes consistingof two or three people, has longgone. Instead nowadays an entire team of hundreds of individuals aretasked with the job of designingthe car, due to the levels of complexity involved. In order to work as efficiently and effectively as possiblethedesign team is generally splitinto two particulargroups duringthe design process. One group is responsiblefor the mechanical design of the car.This involves designingand constructingthe chassisand mechanical components likethe suspension system, steering, gearbox among many others. In most cases the engine of an F1 car is not designed or builtin house, rather supplied by a road car manufacture, such as Renault, which will work in partnership with the F1 team to develop the engine. However due to the engine freeze that has been in placewithin F1 for the past several seasons,this area of Formula One car design has been stagnant, with littleallowances given to improve the current breed of engines. Once the mechanical team has designed the inner workings of the car,they can pass on the necessary dimensions to the second design group which is tasked with producingthe aerodynamic design of the car. Essentially theAerodynamic team of designers will begiven the inner skeleton which they can then cover with the bodywork and then attach to it the required aerodynamic features likethe wings. With a Formula One car containingover 3,500 individual components the design process involved is obviously an extremely complex task. The design of the aerodynamic package of a Formula One car on its own is a massiveundertakingwhich involves several stages,each of which is crucial to the final performanceof the completed design. Each stage in the design process of the aerodynamic packageis carried outwith upmost detail and dedication to ensure that the maximum potential of the car is reached. With the aerodynamic packagecontributingmassively to the overall performanceof a Formula One team, vasta mounts of resources and knowledge is poured into the design process in order to allowthe aerodynamicists amongthe design team to utilisethe very latestadvancements in design tools and technologies. 5.1 Initial Design/Conception Before any design can be put into practice,the initial ideasand theories that the design team will have floatingaround in their minds will need to be put on the ‘drawing board’ in order to create a starting point for the design. This isn’tto say that the initial designswill bemade by hand, with very few still choosing to usethis method, although itmust be noted that one of the lastremainingdesigners to still hand drawtheir ideas is also arguably thegreatest to have ever been in the sport, Adrian Newey, who in his own words describes himself as “the last of the dinosaurs”. Before any new parts or ideas arecreated virtually,thelessons learned fromthe previous year’s design will belaid outon the tableto form the initial targets for the new car,as any drawbacks of the previous year’s design would not want to be carried over onto the new car.To go alongsidethese objectives,the design team may also havenew concepts in their minds,or that they have seen on other teams cars,that they wish to
  26. 26. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 25 | P a g e incorporateinto the new design.Again these will need to be added to the drawingboard.Obviously the regulations regardingFormula Onecar design tends to vary from year to year, so any new regulations will also need to be considered on the drawingboard before a startingpointcan be conceived. Havingtaken all theabove into consideration,the design team will havebeen ableto produce an initial conceptof the basis of the car that they wish to build,creatinga visual idea of the location of the key components, such as the gearbox and engine, location within the vehicle. From here two critical parameters to the design of the car can be determined, both of which will dictatethe final design. Firstly the centre of gravity of the new vehiclewill need to be identified,with this pointon the car providingthe placewhere the weight of the car will beconcentrated. When drawingup the initial design for the new car,the design team will wantto placethe centre of gravity as closeto the bottom of the car as possible,in order to create a more stableand balanced design.The centre of gravity will be determined by the distribution of weight between the front and rear of the car,and the top and bottom. The second parameter that needs to be set is the centre of pressureon the car. This pointis crucial to the aerodynamic design of the car as itis the placewhere all theaerodynamic forces actingon the car will be at its most concentrated, in other words the part of the car that will be being forced into the track. This obviously means that the closer to the centre of the car the more balanced and drivableitwill be.The centre of pressurewill be determined by the positioningof the aerodynamic features on the car,therefore having come up with an initial conceptfor the design of the car, the exact location of the aerodynamic features can then be fine-tuned in this initial design to create the optimum position for the centre of pressure. 5.2 CAD Havingdetermined the initial conceptfor the design of the car,and havingset the necessary design parameters, the design team will then be ableto proceed to realisethese design ideas in a virtual sense. Whereas before these designs would have been produced by hand, hence Adrian Neweys use of the word “dinosaurs”, the initial designs for themodern day Formula One car are carried outwith the useof CAD. All areas of a Formula One cars design will berealised in a CAD environment, with teams usingthe very best CAD packages,such as NX and Catia.CAD provides a 3D virtual environment in which designers can move their ideas into reality,without incurringthe costof physically constructingthe component. CAD is used to create the initial design of all aspects of a Formula One car,however it is in regards to the aerodynamic design of the car where its potential is realised to great success. With the initial design conceived,the relevant data is then passed on to the CAD engineers who produce a virtual 3D model of the design in CAD. Each individual featureof the aerodynamic packagefor a Formula One car will be produced in CAD, with massiveemphasis puton the accuracy of the models, as any slightdifferences between the virtual model and its real lifecounterpart could render any subsequent data, which is obtained duringthe design and testing process,useless.Each partcreated within the CAD environment will be thoroughly tested and validated to ensure that it conforms to the dimensions and geometries that were set duringthe initial design and enablethe predetermined design parameters to be maintained. With the initial design concept produced and validated in CAD, each component is then brought together to create a complete 3D model of the final design.Itis from here that the firstmajor benefit of CAD becomes apparent. The construction of the modern day Formula One car is almost entirely performed through a process called computer aided manufacturing. Designers will beableto pass on the CAD model to the construction team from which the new cars construction can begin to take placethrough the use of the CAD data. The CAD data is used to control the CAM machines,such as a CNC machine, to individually constructthe majority of the components, both aerodynamic and mechanical,thatmake up a Formula One car.
  27. 27. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 26 | P a g e However before the construction of the aerodynamic packagecan commence, the aerodynamicists within the team will look to perform an analysisof each component of the completed CAD model. This aerodynamic analysisof the CAD model is carried out through the use of computational fluid dynamics,or CFD. 5.3 CFD In recent years CFD has become an invaluabletool thathas become a vital partin the design process of a Formula One car. CFD involves the use of fluid dynamic equations to perform detailed analysis of fluid flow within a system, and seeingas air is a fluid itcan beused to analysethe flowof air around a Formula One car. CFD was firstused in the sport of Formula One in the 1990s,and with modern computers becoming ever the more powerful, with this increasein power being far cheaper to purchase,the use of CFD has become widespread in the design process of a Formula One car. CFD is used in conjunction with CAD in order to analysethe aerodynamic properties of the 3D model , creatingvastamounts of data that give an initial reflection on the aerodynami c potential of the new design. CFD allows designers within Formula Oneto perform detailed analysisof any component of the design of their car,meaning that the component can then be tweaked, through use of the data ascertained fromthe CFD simulation,within the CAD environment in order to improve upon and fine tune the final design. CFD allows the aerodynamicists to perform a simulation of the aerodynamic forces that will be acting upon the car.The data produced from this simulation will allowdesign team to gain an understandingof downforce levels that the new design could potentially achieve.From this data the design team will beable to identify areas of the design that can be improved upon in order to produce more downforce. This benefit of running simulations,and obtainingfeedback on the design very quickly, means that the model can be constantly modified before it is sentfor construction. The key to CFD providingsuch a useful design tool is the visualization,in theform of 3D graphics as seen in figure5.1, of air flowover the CAD model that itprovides to the design team. The data produced by the CFD simulation isthen translated by the CFD software in the form of this visual representation of the air flow, allowingthe designers to actually seewhat is happening with their design.This is vital as itallows designers to optimize certain components, such as the front wing, to improve the flow of air runningover the whole car The visual representation also displays therelevant pressure and velocity values that would be present at each area of the model, meaning the design team will beableto see whether there theories will actually producethe desired effect in reality. CFD is particularly useful in thedesign of new innovations or concepts that designer may visualizein their minds,but cannotreplicate in a wind tunnel environment. One example of this is the blown diffuser that uses exhaust gases to improve the flow of air over the diffuser,a situation thatcannot easily betested in the wind tunnel due to air temperature and density differences to those that would be seen in reality.However such a scenario can be simulated usingCFD, as such the innovation can be realised in the CAD environment and then tested through the useof CFD to determine whether it has potential or is better left alone. Figure 5.1 www.eng.fea.ru
  28. 28. [INVESTIGATION INTO THE AERODYNAMIC DESIGN OF A FORMULA 1 CAR] DANIEL BAKER 2013 27 | P a g e CFD has become such a powerful tool in recent times that some racecars within the motorsport world have been entirely designed through the use of CFD, bypassingwind tunnel testing altogether. This method of design has seen some success stories,such as theAcura ARX-02A LMP car that won multipleraces in the American Le Mans series.However with the complexities of designinga modern Formula One car,this success has notbeen replicated in this sport.The Virgin RacingVR01 is an example of a F1 car designed fully in CFD, which was terribly slowin comparison to other cars on the grid,provingthat CFD cannot be fully trusted. For this reason CFD is used hand in hand with wind tunnel testing. 5.4 Wind Tunnel Most of the initial aerodynamic evaluation of a Formula One cars design will becarried outthrough the use of CFD. Wind tunnel testing is then performed on the design as a means to verify the numbers and air flow that were seen in the simulation. Wind tunnel testing will allowthe aerodynamiciststo see the real downforce levels and air flowthat the design will produce,and from there finetune the final design to iron out any issues thatmay not have been seen in the CFD environment. The reason for usingCFD for the majority of the evaluation process is the increased costand difficulty of modifyinga wind tunnel model in comparison to a CAD model. Wind tunnel testing is carried out through the use of scaled models which are generally 60% the sizeof a finished Formula One car,mainly due to the extra costinvolved in producinga full scalemodel. The disadvantageof usingscaled models in the wind tunnel, as opposed to a full sizereplica,is thefactthat there will beminimal differences of the aerodynamic properties of the air surroundingthe model compared to that of the air that would surround the actual working car.One example of this is the boundary layer on the scalemodel, which will bethinner than that on the real car;as a consequence designers will takeissues such as thisinto accountwhen analysingthedata obtained from the wind tunnel. The scaled models used in the wind tunnel, despite the differences as mentioned above, are still an exact replica of the final finished design thatwould hitthe track, just60% of the size. These models are created through the use of a method called rapid prototypingthat can be used to produce a physical construction of the 3D CAD model that would have been drawn up duringthe design. Duringthe operation of the wind tunnel the scalemodel is suspended from the ceilingin order to create a weightless model, meaning that only the aerodynamic forces actingon the model will beshown in the final results.As well as this wind tunnel test will berun with replicasof the pneumatic tyres that would be used in reality,so to ensure that the readings taken from the test take the deformation of the tyres that will be seen on the track into account,this is crucial asthis deformation would affect the airflowover the rest of the car.Once the design is verified and fine-tuned in the wind tunnel the CAD models can be sent for construction in preparation for the final stageof the design process that will be performed, the track testing. 5.5 Simulation Recent years has seen the use of simulation tools,such as a driver simulation,become an integral part of the design process. Once the design of a Formula One car is evaluated through the use of CFD and wind tunnel testing the numbers obtained from these can be use alongsideseveral complex mathematical models to run a simulation of howthe car will perform on the track.This simulation,although primarily for the drivers benefit, can be put to use to gain a better understandingof how the various aerodynamic features of the design may affect the handlingand characterises of the car in reality.A simulation will also givethe driver an opportunity to give the design team initial feedback on any design modifications thatthey may be developing, as the driver will beableto identify the impact that these changes will haveon the handlingof the car.

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