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

Abstract

SummaryBasic aerodynamic characteristics of a generic open-wheel race car equipped with various aerodynamic devices are studied. The focus is on the influence of car underbody design and the front and rear wings on aerodynamic forces experienced by the car. Computational simulations are carried out assuming the steady viscous fluid flow and using the Reynolds-averaged-Navier-Stokes equations and the standard shear stress transport (SST) k-ω turbulence model. The lift force in the configuration with a flat car underbody (without a rear diffuser at the trailing edge of the car underbody) and without the wings is positive (undesirable upforce), while a negative lift force (favourable downforce) is obtained in all configurations with aerodynamic devices (underbody rear diffuser, front wing, rear wing). The aerodynamic devices create an increased, undesirable drag force in comparison with the configuration without the aerodynamic devices. The downforce and the drag force are similar when wings consisting of two and three elements are used. This indicates that, for the same overall chord and wind incidence angle, the number of wing elements is not a very important factor influencing the aerodynamic loads experienced by this type of open-wheel race car with a similar front and rear wing layout. The optimal configurations with respect to the lift-to-drag ratio are those with the rear diffuser and wings in place. In the configuration with threeelement wings, streamlines in the region of the rear wing are analysed both computationally and experimentally using the tuft flow technique. Good agreement between the computational and limited experimental results regarding streamlines is achieved. However, this would need to be further analysed quantitatively in order to fully validate the developed computational model. Key words:Race car aerodynamics, car underbody and wings, computational simulations, field experiments. IntroductionRace cars can experience extreme aerodynamic loads during the race due to various devices designed to optimize the race car aerodynamics, e.g. rear diffuser at the trailing edge of the car underbody as well as the front and rear wings on the car body [1]. The main focus is on enhancing the aerodynamic downforce that generally improves the car traction and stability, while simultaneously trying to avoid a considerable increase in the drag force as it Aerodynamic properties of passenger and race cars are commonly studied experimentally in wind tunnels, but significant efforts are made in the computational fluid dynamics in order to improve its reliability and accuracy for that purpose [3]. Therefore, the development of car aerodynamics nowadays commonly combines wind-tunnel experiments, field measurements and computational simulations.Reference [4] points out the importance of improving the cornering ability of race cars. Aerodynamic devices have been developed for the Formula SAE car, with a special focus on the rear diffuser, and the front and rear wings, as reported in [5]. The flow field around th...

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