STUDY OF FRONT WING OF FORMULA ONE CAR USING COMPUTATIONAL ... · PDF fileSTUDY OF FRONT WING OF FORMULA ONE CAR USING COMPUTATIONAL FLUID DYNAMICS ... analysis method and techniques

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Int. J. Mech. Eng. & Rob. Res. 2014 Aniruddha Patil et al., 2014

STUDY OF FRONT WING OF FORMULA ONE CARUSING COMPUTATIONAL FLUID DYNAMICS

Aniruddha Patil1*, Siddharth Kshirsagar1 and Tejas Parge1

*Corresponding Author: Aniruddha Patil,[email protected]

The 222 member organization worldwide and one of the richest sports Federation Internationalede Automobile (FIA) Formula 1 World Championship proposed new aerodynamic rules for 2009season. The main intentions and goals were to reduce the downward force by 50% and improvingthe sensitivity of the car running at an average speed of 175 kmph. The CFD simulations pointthat the main factor contributing in the field of new aerodynamic rules and regulations is thedesign of front wing of F1 car. Till date steady state CFD simulations have been carried out withdifferent add on devices like front wing, roof spoiler, nose wing, bargeboard at different speedsin order to improve aerodynamic performance. Front wing is vital component because it iswhere air first meets the car. Entire aerodynamic performance of an F1 car can be changed bysubtlest of alterations in front wing design.

Keywords: Computational fluid dynamics, Down force, Drag, End plates, Front wing, Lift

INTRODUCTIONWhile designing a Formula One car the mostimportant and significant aspects the designerhas to deal with, is the field of aerodynamics.The aerodynamic designer has two primaryconcerns: the creation of down force, to helpthe car steer onto the track and improvecornering forces; and minimizing the dragforce, caused by turbulence which in turndecreases the speed of the car (Mohd SyazrulShafiq Saad, 2010). These factors enhancethe performance of the car.

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1 Department of Mechanical Engineering, University of Pune, Maharashtra, India.

The front wing of the Formula One car isthe single most crucial aerodynamiccomponent. This is because the front wing ofthe car influences the flow of air over the restof the body since it is the part, which firstcomes in contact with the air. It also influencesthe flow of air into the brake ducts, radiatorand diffuser and also to the main engine intake.Down force is generated by the front wing dueto the ground effect where more force isgenerated when aerofoil is moving close to theground surface. This is one of the many factors

Research Paper

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that are influenced by the front wing. The wingalso incorporates many small cascadingwinglets which refine the flow and ensures thatthe flow is laminar and attached to the body ofthe car in order to attain good aerodynamicsresult.

The Formula One is a very competitive eventin which small improvements in the design ofthe car may largely affect the car ’sperformance. Hence the use of robust andconcrete technology is necessary to producethe best possible design for higherperformance. CFD is one of thosetechnologies. CFD, abbreviation ofComputational Fluid Dynamics, is a branch offluid mechanics that uses numerical methodsand algorithms to solve and analyze problemsthat involve fluid flows. The flow of any fluidcomprises of three main principles which are:

• Conservation of mass.

• Newton’s second law of motion.

• Energy conservation.

These fundamental principles can beexpressed in terms of mathematical equations,which in their most general form are usuallypartial differential equations. ComputationalFluid Dynamics (CFD) is the science ofdetermining a numerical solution to thegoverning equations of fluid flow and helps tosimulate the flow of fluid over the field ofinterest.

CFD allows engineers to examine theairflow over an automobile or a particular partsuch as a wing or hood and see theaerodynamic effect and, helps to solvecomplex problems without losing their integritydue to ease of the software. The main

advantages of using CFD software is that theresults are obtained without construction of therequired prototype and this is very importantbecause it can reduce the cost in constructingthe F1 cars. The validity of results is the mostimportant thing that we need to concern aboutwhile using the software simulation. Thereforespecific parameters and conditions whileanalysing the data need to be valid. Amongvarious components that contribute to thevarying levels of down force it is the front wingthat lends itself to theoretical aerodynamicanalysis method and techniques for designusing the CFD software.

The role of CFD in engineering predictionshas become so strong that today it may beviewed as a new third dimension of fluiddynamics, the other two being pureexperimentations and pure theory.

OVERVIEW OF FRONT WINGOF FORMULA ONE CARFront wing of Formula One car is the singlemost crucial aerodynamic component. Thecontributing factor for the above statement isthe manner in which it influences the flow of airinto brake ducts, radiators, diffusers and alsomain engine intake. The front wing is actuallymade into readily modifiable componentswhere flaps and small winglets provide differentlevels of down force distribution as per thehandling requirement of the driver during therace. The dynamic balance of the Formula Onecar is determined by load on the front wingwhich is required to be easily modified.

The basic front wing of the Formula One carconsists of main plane, a pair of aero-flaps anda pair of end plates. The first element of thewing is rectangular in shape which provides

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air flow to the second element lower surfaceso that the latter’s incidence may be increasedat a very high angle.

Now a day’s front wing is of two or threeelement aerofoil which is not actually straightalong its span. On the other hand the main flapis a rectangular platform having differentshapes due to downstream flow constraints.Aerodynamic down force on the Formula Onecar is not only generated by the difference inthe air pressures on two sides of the mainplane but also use to aerodynamic theory ofventure. The venture theory shows that byreducing height of the main plate to ground,the velocity of air flowing through is increasedand low air pressure is created which resultsin further down force.

Many researchers have studied the meansto enhance the aerodynamic performance andalso the effect these changes have on theoverall performance of the car employinganalytical and experimental methods. Differentaerofoil shapes were considered for thedesign and were analysed during cornering,straight line braking and straight lineacceleration conditions. These shapes weretried for single and dual wing configurations.The results showed the importance ofmaintaining a proper lift to drag ratio and thatthe front wing down force had to balance therear wing down force for optimal results.

Comparatively the front wing of an F1 carhas a lot of constraints unlike the rear wing andother parts. It is required to have a neutral

Figure 1: Details of Front Wing

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central section and for a fruitful purpose it mustbe at least 50 cm in length and cannot induceany amount of down force, hence it is calledas neutral central section. There is freedomthough in the number of cascades and theflexibility of the wings it is not availing to specifyor limit the number of cascades and itsflexibility before actual design is done and testsare carried on it. It is found that the stability ofa car, while slipstreaming, improves when thewings are flexible. Also the point to beconsidered is that the closer the wings are tothe ground, the more is the down force that itproduces, since it makes use of the groundeffect of the car. But according to theregulations specifications the minimum groundclearance of the car at standstill position whichcannot be compromised on. Hence in orderto make utmost use of this regulation flexiblewings are added which move down duringcornering which induces a higher down forceon the car and improves its handling andstability. The combined effect of the abovefactors proves to be the heart of design of frontwing of the Formula One car considering theaerodynamics point of view using CFD.

Lift Force and Drag ForceWhen a fluid moves over a stationary objectthe lift, down force is generated perpendicularto the direction of travel for any object. On theother hand drag force is unavoidableconsequence of an object which is generatedparallel and in opposition to direction of travelfor any object (Mohd Syazrul Shafiq Saad,2010).

Drag force can be divided into twocomponents—the pressure drag which isdependent on shape of any object movingthrough a fluid and skin friction drag which is

dependent on viscous friction but a movingsurface and fluid derived from wall shearstress. The lift and drag force depend on thedensity of the fluid, the upstream velocity V,the size, shape and orientation of the body.Lift and drag coefficient can be defined as:

Lift co-efficient:AV

FLCL22/1

Drag Co-efficient:AV

FDCD22/1

Two wings will produce less than twice thedown force produced by a single wing. Liftcoefficient and the ratio of Lift to Drag (L/D)decreases with increasing number of air foils.Earlier CFD was first developed to achievethe target lift and drag coefficient for 2D frontwing design. But now maintaining high liftcoefficient plays a crucial role in designing andtesting of Formula One car’s front wing usingCFD package. Due to the very low aspectratios of race car wings, the primary source ofdrag comes from the induced component ofoverall drag (Sriram Saranathy Pakkam,2011). Two primary components which affectthe lift and drag force are the shape of bodyand use of air foils. As it is evident that thefront wing is sensitive to both angle andorientation as well as down force of drag itwould not be wrong to conclude that with a viewto achieve the goal of highest lift to drag ratio,the design of front wings anticipated by eachand every F1 car franchise proves to be fruitfulin doing so.

Role of the End PlatesAmong different components of front wing likemain plane, cascade winglets, curved vanes,flaps and nose pylons, one very important part

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is the end plate which is used to redirect theairflow around front tires. By directing theoncoming airflow around the front tires,minimizes the amount of drag resistanceproduced and allows the air low to continueback to side pods and cars floor.

End plates can be found at the limit of thewing, be it front or the rear wing, The size ofthese elements are dictated by the airregulations as they can be influential to thewings profile they are connected to. End plateincreases the wing aspect ratio without theneed to increase its wing span leveragingmore down force. The end plates function issimilar to the winglets on aircraft, that is toseparate the negative pressure on the bottomof the wing flowing and the positive pressureon the top of the wing which eliminates induceddrag. The other functions of end plates is toincrease the aerodynamic efficiency whiledesigning we cannot neglect the fact that whenthe endplate area is increased overall liftcoefficient increases while there is significantreduction in drag coefficient. Over the timewheels were moved closer to the chassiswhich created unnecessary turbulence in frontof the wings, further reducing aerodynamic

efficiency and contributing to unwanted drag.In order to overcome this problem the teamsmade inside edges of front wing end platescurved to direct the air from of chassis.

With the advent of new technical designsavailable due to CFD analysis there has beenfurther front wing end plate design updates.Amongst the latest work into detailing of endplates, one of the features is attachment ofshorter and less vertical fin and other is use ofsquared end to the upper element of end plate.

Front Wing Before and After 2009The year 2009 proved to be beginning of thenew era in the history of Formula One racingsince the introduction of new technical ruleswhich closed off several areas foraerodynamic development. As a result the frontwing became one of the most important areasof car development as the designers had thefreedom to make changes and limit the scopefor improvement.

Recalling the time period before 2009, thefront wing design was simple, boxy, with verysquare end plates which had the single functionof pushing air around the front tires. Thougheach and every team followed a different andmore refined concept than other teams, thebasic front wing itself was a simple threeelement device without any cascades orappendages. The most important physicalfactor contributing in the field of designing isthe weight of the F1 car which was 640 kg.But as a result of use of servo and associatedelectronic equipment’s along with storage ofballast contributed to further increase in weightwhich led to imbalance of the car design as aresult making them bulky.Many Formula Oneconstructors began to do the same thing and

Figure 2: Endplate

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many wings flourished on the Formula 1 circus.The wings were fixed on the wheel hubs of thecar to transfer the load directly to the wheelsallows avoiding stiffening the springs of thesuspension system that might create instabilityon undulating tracks (Mortel, 2003).

Changes made in the regulations from2009 improved the entire body work of the caras a result reducing overall down force levelsto allow closer racing. Drastic changes weremade in the basic front wing design changingits width from 1400 mm to 1800 mm andlowering from 150 m to 75 mm from thereference planes which is the lowest point ofthe car. Earlier driver was allowed to performadjustments to the main flap of the front wingtwice a lap by 6 degrees, but now the front wingcan only be adjusted manually only once in thepit lane. Upper cascade winglets have beenadded which are connected via end plates andthe main plane, aid in guiding the air flowreducing the drag. The major front wingchanges during the season are very rarelyseen in one go because the rest of the carrelies on the front wing design considering theaerodynamic point of view.

The main plane of the front wing and thevarious flaps are now being merged into one,with various slot gaps appearing in the wing.The flaps no longer connect directly to the mainplate instead the main plane and the flaps nowform their own end plate in the form of turningvane. This allows improved air flow redirectionand improves the overall end plate design. In2010, Red Bull brought a new design conceptin to use “Flexi-wings” which allowed the wingsto flex to a large degree and closer to the tracksurface thus giving the ability to the car to turninto corners much better than other cars at high

speed. As the time passed, the importance ofadjusting Front Flap Angle (FFA) increasedthus resultinga drastic change in the carbalance as the race develops.

CONCEPT AND USAGE OF CFDCFD is a computational technology thatenables researcher to study the dynamics ofthings that flow. Using CFD, a computationalmodel that represents a system or device canbe build. Then the fluid flow physics andchemistry can be applied to this virtualprototype and the software will output aprediction of the fluid dynamics and relatedphysical phenomena. Therefore, CFD is asophisticated computationally-based designand analysis technique. Besides that, CFDsoftware can give the power to simulate flowsof gases and liquids, heat and mass transfer,moving bodies, multiphase physics, chemicalreaction, fluid-structure interaction andacoustics through computer modelling. UsingCFD, the product will get to the market fasteras result it can save time that used for buildingprototype. CFD is commonly used foraerodynamics of air craft and vehicles (lift anddrag), hydrodynamics of ships, power plantcombustion (I.C engines and gas turbines),marine engineering (loads on off shorestructures) and meteorology (weatherprediction) (Mohd Syazrul Shafiq Saad, 2010).Considering the design requirements we canconclude that the aim of CFD is to resolve theequation that drives theoretically every kind offlow using continuity and momentum equation.

In CFD simulation, it is easier to optimizeand change certain features in the designrather than changing the shape of prototype inthe wing tunnel tests. This is a significant

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advantage as it leads to a reduction in time. InFormula One not only case of aerodynamicscan be used in CFD. CFD also can be usedto monitor the heat transfer from the brakes.Formula One brake comprise of carbon fibrediscs with carbon fibre brake pads. It is vital toensure that the optimum air flow is achievedfor engine induction in the engine intakeopening. This can be done by using CFD.Hence, the air flow can be optimized toincrease the power of the engine. Anotheradvantage of CFD is that the level of detail ofthe data that is obtained from the solution iswide. This data can be viewed from differentperspectives, which is a big advantage.

DESIGN PARAMETERS ANDFEATURESDesigning of front wing of a car is mainlydependent on the Bernoulli’s principle whichcomprises that air flowing over the differentside of the wings creates a pressuredifference when the air travels differentdistances over the contour of the wing. As thispressure tries to balance, the wing tries tomove in the direction of the low pressure.Planes use their wings to create lift, whereas

race cars use theirs to create down force.Efficient designing of the front wing helps theFormula One car to create cornering force ofup to 3.5 g due to aerodynamic down force.

Role of CFD in field of design changes anddepends on phase of study. The numericalmodel is set up and run using CAD softwarewhich produces boundary conditions foranalysis. This analysis result plays a veryimportant role in optimizing designcomponents such that there should beminimum drag and maximum negative lift.Earlier CFD solutions were computed with thehelp of 2D simulations which was consideredideal. But as it was not feasible to build a 2Dgrid without one element thickness in Zdirection, 3D simulation was thus undertaken.This simulation could solve for each angle ofattack even though it would require immenseamount of computational resources andproportional amount of time.

Effective design for the 19 Grand Prix heldin one season the analysis of the front wingusing CFD is possible mainly by using 2types:

Grid Generation (Meshing)Any design flow under considerations dividedinto shapes like triangles and quadrilateralsalong with some assumptions of flowproperties. Grid or mesh generation is usedonly while designing complex geometries andwhen lower cell count is desired because ofsmaller gradients. Grid generation is by far oneof the most crucial processes of CFD analysisas the grid chosen can make or break thenumerical solutions.

Based on association of cells there are twotypes of grids:

Figure 3: CFD Analysis of F1 Car

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Structured GridIn this grid the computational cells can beassociated with ordered triplet of indices thatare independent and have a fixed range. Theadvantage of using structural grid is that thenumber of cells in the entire mesh can easilybe associated with their index direction. Basedon the general shape of the grid the structuredgrid can be O-type grid, C-type grid and H-type grid.

Unstructured GridUnlike the structured grid this grid consists ofgrid points placed in flow fields in a veryirregular fashion. Thus unstructured gridrequires more information to be stored andrecovered than structured grids.

As the front wing of Formula One carconsists of many parts of any arbitrary shape,Finite Volume Method (FVM) is preferredwhich demands a structured meshes. The FVMallows meshing to be performed using thetriangulation method for all the surfacesfollowed by creation of tetrahedral mesh in thevolume bounded by the wing.Despite recentgains made In aerodynamic design, there isstill little known about the influence that race-car wings have on the production of a car’soverall downforce (William Jasinski andMichael Selig, 1998).

Modelling with Help of Solver ModelsSimulation of front wing of Formula One carwhich is a single element configuration

Figure 4: Grid Generation (Meshing) of F1 Car

Figure 5: Grid Generation (Meshing)of F1 Car

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said that even the slightest changes in thedesign of the end-plates may affect theperformance of the front wing of the FormulaOne race car. When the endplate area isincreased, overall lift coefficient increaseswhile there is a significant reduction in dragcoefficient. Therefore, it is one of the importantdesign aspects which are to be considered.From the above study we can conclude thatdrag reduction is the primary and the mostbasic parameter regarding the design andperformance of the Formula One car (Shi Sunet al., 2013). Hence, drag minimization is thekey design criterion in Formula One.

Moreover, the above study was highlyeducational regarding the fields ofaerodynamics, f luid dynamics, CFDsimulations and automobile design (SatyanChandra et al., 2011). Further the performanceof the car and its aerodynamics wereevaluated and if the simulations were not upto the mark then necessary recommendationsand suggestions were provided. With the aidof Computational Fluid Dynamics (CFD)simulations the development cycle and overallcost were greatly reduced while new andcreative ideas were easily tested on the virtualplatform with accuracy.

ACKNOWLEDGMENTInspiration and guidance are invaluable inevery aspects of life, especially in the fields ofacademics, which we have received from myrespected review paper guide. We would liketo thank him as he was responsible for thecomplete presentation of my seminar and alsofor his endless contribution of time, effortvaluable guidance and encouragement he hasgiven to me.

comprising of two sections on either side ofits nose, concentrates on the angle of attackand the effect of the ground on lift and drag.Preparation of physical model helps us todetermine the amount of computer resourcesrequired for future work. With the help ofphysical model generated the two dimensionalapproach can be easily applied to anyproblem. The wings of Formula One car areinverted at a certain angle of attack whichcreates down force instead of lift. By preparingthe actual physical model we can validate theconcept of positive angle of attack which furthercontributed in determining braking,acceleration and cornering force of the racecar. On the other hand the geometric modeldesigned using computer modelling (CADsystem) is necessary for making changesduring the numerical simulation procedure.

The main advantage of following the abovetwo design procedures in CFD is that thecandidate design which is being produced caneasily be compared against a backdrop of therequired parameters.

CONCLUSIONFrom the above study, it can be said that theperformance of the front wing of the FormulaOne car is greatly affected by the existence ofground nearby. The nearby ground helps todevelop a large net down force, also knownas the negative lift when the flow is simulatedwith the ground effect (Kieffera et al., 2005).After studying the analysis of the model it canbe inferred that the vertical plate deflects theflow of air, thus reducing the drag force andalso further prevents the super pressure thewheel to extent to multi-element air foil surfacesthereby increasing the down force. It can be

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REFERENCES1. Kieffera W, Moujaesb S and Armbyab N

(2006), “CFD Study of SectionCharacteristics of Formula Mazda RaceCar Wings”, Mathematical andComputer Modelling, Vol. 43, Nos. 11-12, pp. 1275-1287.

2. Mohd Syazrul Shafiq B Saad (2010),“Study of F1 Car Aerodynamics FrontWing Using Computational FluidDynamics (Cfd)”, Universiti MalaysiaPahang, December.

3. Mortel F (2003), “Cranfield Team F1: TheFront Wing”, © Cranfield University.

4. Satyan Chandra, Allison Lee, StevenGorrell and C Greg Jensen (2011), “CFD

Analysis of PACE Formula-1 Car”,Brigham Young University.

5. Shi D Sun, Pattarapong Thannipat andHadi Winarto (2013), “Airfoil ShapeOptimization for a Formula One Car FrontWing Using Multi-Objective GeneticAlgorithm”, Royal Melbourne Institute ofTechnology, Bundoora, Victoria, 3083.

6. Sriram Saranathy Pakkam (2011), “HighDownforce Aerodynamics forMotorsports”, M.Sc. Thesis Submitted toGraduate Faculty of North Carolina StateUniversity, North Carolina.

7. William J Jasinski and Michael S Selig(1998), “Experimental Study of Open-Wheel Race-Car Front Wings”, Society ofAutomotive Engineers, Inc.

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