Open Wheel Race Car Research Articles

Computational Investigation of the Aerodynamics of a Wheel Installed on a Race Car with a Multi-Element Front Wing

The search for high aerodynamic performance of a race car is one of the main aspects of the design process. The flow around the basic body shape is complicated by the presence of the rotating wheels. This is especially true in race cars on which the wheels are not shrouded, where the effects on the flow field are considerable. Despite this, few works have focused on the flow around the rotating wheels. In this paper, CFD techniques were used to provide a detailed analysis of the flow structures generated by the interaction between a multielement inverted wing and the wheel of an open-wheel race car. In the first part, the CFD approach was validated for the isolated wheel case by comparing the results with experimental and numerical data from the literature. The wheel was analyzed both in stationary and unsteady flow conditions. Then, the CFD model was adopted to study the interaction of the flow structures between the wheel with the real grooves on the tire and the front wing of a Formula 1 car. Three different configurations were considered in order to differentiate the individual effects. The discussions were supported by the values of the aerodynamic performance coefficients and flow contours.

Performance Analysis of Multiple Intake Design Methodologies for an open Wheel Race Car Vehicle using Different Simulations

Performance Analysis of Multiple Intake Design Methodologies for an open Wheel Race Car Vehicle using Different Simulations

Passive variable rear-wing aerodynamics of an open-wheel racing car

A rear wing designed to improve motoring performance and enhance stability during cornering needs to generate a large downforce at a relatively low speed. If the angle of attack of the rear wing is large, then air resistance is increased during high-speed driving, and thus, fuel consumption is increased due to the large drag values. On the other hand, the performance on high-speed cornering will improve overall lap time with an increased angle of attack. To mitigate this disadvantage, we aimed to reduce the angle of attack during high-speed driving to reduce downforce and drag and thus to reduce fuel consumption. Meanwhile, during low-speed driving, for example in cornering, the angle of attack was increased and a large downforce generated to improve driving stability. In order to achieve both goals, we developed a passive-type variable rear wing. This rear wing was designed to have a three-step shape where the second step in the center was designed to swing. We first confirmed the behavior through both computer-aided engineering analysis and wind tunnel experiments, and then we constructed a full-size rear wing and measured the downforce on a student Formula SAE vehicle. The results showed that it is possible to generate a downforce of 80 N at a low speed of 30 km/h (8.3 m/s) and a downforce of 145 N at a high speed of 50 km/h (13.9 m/s).

Aerodynamic Performance of the Underbody and Wings of an Open-Wheel Race Car

Aerodynamic Performance of the Underbody and Wings of an Open-Wheel Race Car

Numerical simulation of flow field around the race car in case

Purpose – The purpose of this paper is to gain a better understanding of the flow field structure around the race car in two cases: stationary wheel and rotating wheel. In addition, this paper also illustrates and clarifies the influence of wheel rotation on the aerodynamic characteristics around the race car. Design/methodology/approach – The author uses steady Reynolds-Averaged Navier-Stokes (RANS) equations with the Realizable k-ε model to study model open-wheel race car. Two cases are considered, a rotating wheel and stationary wheel. Findings – The results obtained from the study are presented graphically, pressure, velocity distribution, the flow field structure, lift coefficient (Cl) and drag coefficient (Cd) for two cases and the significant influence of rotating case on flow field structure around wheel and aerodynamic characteristics of race car. The decreases in Cd and Cl values in the rotating case for the race car are 16.83 and 13.25 per cent, respectively, when compared to the stationary case. Originality/value – Understanding the flow field structures and aerodynamic characteristics around the race car in two cases by the steady RANS equations with the Realizable k-ε turbulence model.

CFD Investigation of the Effect of the Salient Flow Features in the Wake of a Generic Open-Wheel Race Car

It is well known that in motorsport the wake from an upstream vehicle can be detrimental to the handling characteristics of a following vehicle, in particular in formulae with high levels of downforce. Previous investigations have been performed to characterize the wake from an open wheel race car and its effect on a following car, either through the use of multiple vehicles or purpose-built wake generators. This study investigates how the wake of an upstream race car impacts the aerodynamic performance of a following car in a close-following scenario. Wakes are imposed on the inlet of a CFD simulation and wake parameters (eg: velocity deficit, trailing vorticity) are directly manipulated to investigate their individual impacts on the following vehicle. The approach provides a useful alternative to the simulation of multi-vehicle cases but a better simulation could be achieved by including wake unsteadiness from the upstream vehicle. Arguably the most significant impact of a wake on the following vehicle was found to be the rearward movement of the vehicle center of pressure. Secondary flow (eg: upwash, vorticity) on a bulk scale had the beneficial impact of moving the wake up and over the following vehicle but more localized impacts could be positive or negative according to the detailed interaction with downstream vehicle features.

Flow compressibility effects around an open-wheel racing car

AbstractA numerical investigation has been conducted into the influence of flow compressibility effects around an open-wheeled racing car. A geometry was created to comply with 2012 F1 regulations. Incompressible and compressible CFD simulations were compared – firstly with models which maintained Reynolds number as Mach number increased, and secondly allowing Mach number and Reynolds number to increase together as they would on track. Results demonstrated significant changes to predicted aerodynamic performance even below Mach 0·15. While the full car coefficients differed by a few percent, individual components (particularly the rear wheels and the floor/diffuser area) showed discrepancies of over 10% at higher Mach numbers when compressible and incompressible predictions were compared. Components in close ground proximity were most affected due to the ground effect. The additional computational expense required for the more physically-realistic compressible simulations would therefore be an additional consideration when seeking to obtain maximum accuracy even at low freestream Mach numbers.

On the interaction of a racing car front wing and exposed wheel

AbstractA numerical investigation of generic open-wheel racing car wing and wheel geometry has been conducted, using original sub-scale experimental data for validation. It was determined that there are three main interactions that may occur, identifiable by the path that the main and secondary wing vortices take around the wheel. Interaction ‘A’ occurs when the main and secondary wing vortices both travel outboard of the wheel; interaction ‘B’ is obtained when only the main wing vortex passes inboard of the wheel; while interaction ‘C’ sees both wing vortices travel inboard of the wheel. The different interactions are achieved when geometric changes to the wing affect the pressure distribution about the endplate, either by altering the magnitude of suction generated by the wing or by changing the locations of peak suction and vortices relative to the wheel’s stagnation regions. As a result, the influence that the wing and wheel have on each other – in comparison to the same bodies in isolation – varies, resulting in significant consequences for downforce and drag.

Physical characteristics of experienced and junior open-wheel car drivers

Despite the popularity of open-wheel car racing, scientific literature about the physical characteristics of competitive race car drivers is scarce. The purpose of this study was to compare selected fitness parameters of experienced and junior open-wheel race car drivers. The experienced drivers consisted of five Formula One, two GP2 and two Formula 3 drivers, and the nine junior drivers drove in the Formula Master, Koenig, BMW and Renault series. The following fitness parameters were tested: multiple reactions, multiple anticipation, postural stability, isometric upper body strength, isometric leg extension strength, isometric grip strength, cyclic foot speed and jump height. The group differences were calculated using the Mann-Whitney U-test. Because of the multiple testing strategy used, the statistical significance was Bonferroni corrected and set at P < 0.004. Significant differences between the experienced and junior drivers were found only for the jump height parameter (P = 0.002). The experienced drivers tended to perform better in leg strength (P = 0.009), cyclic foot speed (P = 0.024) and grip strength (P = 0.058). None of the other variables differed between the groups. The results suggested that the experienced drivers were significantly more powerful than the junior drivers: they tended to be quicker and stronger (18% to 25%) but without statistical significance. The experienced drivers demonstrated excellent strength and power compared with other high-performance athletes.

Cardiac chronotropic adaptation to open-wheel racecar driving in young pilots

Objectives: we aimed to evaluate heart rate (HR) response in pilots to repeated bouts of race car driving.Design and methods: Eight young male student pilots (18.75 ± 3.41 years) participated to a training session consisting in 5 successive bouts (27.81 ± 1.50 min) of driving a “Formula academy” open-wheel race car on the “Bugatti” Speedway of Le Mans (France) . Mean and peak speeds were calculated after lap duration measurement using a telemetric infrared timing device. HR was recorded continuously on 5-second intervals using a portable cardiometric device.Results: when driving at a mean 134.94 ± 2.96 km/h speed, mean HR was 132.71 ± 10.71 bpm corresponding in 67.88 ± 5.37 %HRmax intensity. No significant differences were found between the different driving bouts whatever the parameters considered.Conclusions: these results showed good repeatability of the measurements and they suggested that HR monitoring is a valid method to evaluate racecar pilot adaptation to driving . Moreover, the lack of relationships between duration variation, mean or peak speed and HR all along the experiment confirms the major role of muscle isometric loads on energy expenditure and therefore on HR when driving a “Formula academy” open-wheel racecar.

Open-Wheel Race Car Driving: Energy Cost for Pilots

The aim of this study was to evaluate the energy cost of speedway open-wheel race car driving using actimetry. Eight pilot students participated in a training session consisting of 5 successive bouts of around 30 minutes driving at steady speed on the Bugatti speedway of Le Mans (France). Energy expenditure (EE, kcal) was determined continuously by the actimetric method using the standard equation. Energy cost was estimated through physical activity ratio (PAR = EE/BMR ratio, Mets) calculation after basal metabolism rate (BMR, kcal·min-1) estimation. A 1-met PAR value was attributed to the individual BMR of each volunteer. Bout durations and EE were not significantly different between driving bouts. Mean speed was 139.94 ± 2.96 km·h-1. Physical activity ratio values ranged 4.92 ± 0.50 to 5.43 ± 0.47 Mets, corresponding to a 5.27 ± 0.47-Mets mean PAR values and a 1.21 ± 0.41 kcal·min-1 mean BMR value. These results suggest that actimetry is a simple and efficient method for EE and PAR measurements in motor sports. However, further studies are needed in the future to accurately evaluate relationships between PAR and driving intensity or between PAR and race car type.

Vertical Impact to an Open Wheel Race Car and Development of a Crash Test to Simulate Driver Response

Vertical Impact to an Open Wheel Race Car and Development of a Crash Test to Simulate Driver Response

Experimental investigation into wing span and angle-of-attack effects on sub-scale race car wing/wheel interaction aerodynamics

This paper details a quantitative 3D investigation using LDA into the interaction aerodynamics on a sub-scale open wheel race car inverted front wing and wheel. Of primary importance to this study was the influence of changing wing angle of attack and span on the resulting near-field and far-field flow characteristics. Results obtained showed that both variables do have a significant influence on the resultant flow-field, particularly on wing vortex and wheel wake development and propagation.

Use of numerical optimization to determine the effect of the roll stiffness distribution on race car performance

The use of active systems for controlling suspensions has been used before in Formula One and other open wheel racing series but at present this form of active control is not allowed by Formula One regulations. The roll stiffness distribution is a key element of suspension design and it has an influence on the dynamic weight transfer of the vehicle. In this paper, the roll stiffness distribution has been optimized during a calculation process to simulate and quantify the possible benefits of controlling the distribution of roll stiffness between the front and rear axles of an open wheel race car. The roll axis concept has been used to provide the roll component to the lateral load transfer evaluation. The benefits shown by the optimization of the roll stiffness distribution have created a mean handling performance improvement over the base vehicle of over 10 per cent, which on the lap of the Barcelona Grand Prix circuit yielded a lap time improvement of 2.71 s, using a quasi-steady-state calculation method. Additionally, it has been shown how this improvement has been realized in terms of the change in vehicle dynamics. This research also shows that circuit dependent analysis is possible to exploit the value of the static setting of the roll stiffness distribution. Further work and validation are required to explore this avenue of vehicle set-up optimization, but it does appear that the optimized calculation approach offers a way of helping to make an objective choice of a static roll stiffness distribution setting for particular circuits.

A quasi steady state approach to race car lap simulation in order to understand the effects of racing line and centre of gravity location

Using an established seven-degree-of-freedom (7DOF) model of an open wheel race car, a new quasi steady state lap simulation method is described. The method is based on optimal control techniques. It produces a GG speed diagram as an interim result, and is shown to have a low computational expenditure when compared with the current transient optimal control method. This paper shows a validation step, reports a case study using the new method, and compares the result with a transient optimal control method. The sensitivity of the optimal line for simulation studies is discussed in terms of a centre of gravity location change. Both simulation methods show improvements in lap time owing to a 6 per cent centre of gravity set-up change. The difference in optimal lines caused by a 6 per cent CG change rearward is shown to be so small that a driver is unlikely to find the information useful. In light of this observation, the computational effort required to generate a new optimal line for each set-up change may be misspent

Effectiveness of the head and neck support (HANS1) device in frontal impacts of CART cars: a CAE analysis

Results of a CAE (Madymo) analysis probing effectiveness of the HANS device in reducing injuries to open-wheel racecar drivers in frontal impacts are presented. The model utilised a typical impact pulse used in sled tests. Results show that the HANS device significantly reduces upper-neck shear, tension, and extension moment. These results agree with published test data. Upper-neck loads remain lower than the no-HANS case for a wide range of tether stiffness. The same is true for upper-neck shear and tension for increasing tether slack. Results are more sensitive to changes in slack than stiffness. The predicted head injury criterion is higher for drivers with the HANS device. This is attributable to tether forces at the time of engagement, the magnitude and duration of which depend on contact-interaction between head and helmet-inside. Further tests are needed to better estimate this interaction. Results also show that lowering friction on HANS surfaces reduces head-neck injury potential.