Some sports cars such as, for example, the Porsche 918 Spyder, have predefined aerodynamic settings for a specific range of speeds which make it possible to either minimize drag or maximize downforce, while the active aerodynamics of the McLaren Senna additionally enables it to shift the aerodynamics balance towards the rear of the car to enhance braking. The additional aerodynamic elements generate additional drag, so it is desirable to activate the movable elements only when necessary. Typically, such aerodynamic elements have the form of a wing, generating downforce which compensates the lift force generated by the car body. The frailty of the car body shape is typically compensated by fixed or movable aerodynamic elements activated at high speed. Unfortunately, such action has drawbacks in the form of car bodies generating aerodynamic lift forces at high speed, together with a decrease in a car’s directional stability and reduction of safety limits during fast cornering. The external shapes of cars are typically optimized for low aerodynamic drag. The development of the quality of highways together with the increase in the potential maximum speed of cars has turned the attention of car designers towards the dynamic features of cars at high speeds. The authors have shown that the inclusion of a bidirectional fluid structure interaction can lead to a significant change in the aerodynamics forces. The study presented in is in contrast to this assumption. Very often, it is assumed that car movement will not affect aerodynamic forces. However, it is rather rare to take into account the coupling of car dynamics and aerodynamics. These methods attempt to reproduce the test procedure according to the ISO 12021:2010 standard. Studies found in the literature mainly focus on sensitivity to lateral wind.
They need to ensure that stability will be good enough to allow safe driving in all road conditions (wind gusts, moving obstacles, etc.). This situation introduces new challenges for car designers. IntroductionĬurrently, the trend to minimize emissions by limiting fossil fuel consumption leads to lighter cars with a low drag coefficient. This paper presents the methods, assumptions, and results of numerical and experimental investigations by modeling and simulation of the aerodynamic characteristics and dynamics of a small sports car equipped with movable aerodynamic elements operated by an electronic subsystem for data acquisition and aerodynamics active automatic control. The aim of this study was to extend the safety limits of fast moving cars by the application, in a controlled way, of aerodynamic forces which increase as the square of a car’s velocity and, if left uncontrolled, dramatically reduce car safety.
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