The challenge of this project was to design and develop an aerodynamic package that makes use of Active aerodynamic devices in comparison to the static previous designs. Due to the nature of racing teams, R&D is essential and work is always iterative, developing on concepts and designs of previous years. This project was the start of the teams use of active devices.
Active aerodynamics refers to components and systems that are dynamic, meaning that they can change their position, form or properties in order to improve performance. This means that systems could be developed to optimise the vehicles performance in different instances; for example when the car is in a straight line the systems would allow minimum drag from the aerodynamic devices, and when cornering maximising the downforce for improved stability and cornering speed.
The challenge in this case was delving into the unknown. Active aerodynamics were seen as a waste of time and it was thought that the costs outweigh the benefit. This is what had to be proven wrong.
The objective of the project was to reiterate the design of the rear wing to comply with the aero package of the whole bodywork. This design had to incorporate active devices and specifically guage the performance increase that this device will provide. This performance increase was to be compared to the additional costs of the assembly, and the advantage of the device and the design as a whole was to be assessed.
The best use of active areo was to create a drag reduction device, which will allow the wing to be designed in a high downforce setup. The drag reduction device would dramatically reduce the angle of attack of the second and third elements of the wing when activated, stalling them to reduce both downforce and drag. This allows for a "nitrous" like boost when activated, as the large surface area of the wing pushing against the wind is immediatley flattened, with a similar effect to dropping a parachute. This target allowed performance to be optimised for both cornering and straight line speed.
Fig 2: Shows pressure variation accross the wing when air is flowing over it. The higher pressure area above the wing exerts force on the lower pressure underside. This pressure gradient creates the downforce
Fig 2: Final assembly of rear wing in closed position. This model includes the swan neck mount, but does not include the actuation equipment for the active flaps.
APPROACHING THE PROBLEM
The advantage of using computational methods to design and simulate the wing was that the wing could be optimised and simulations could be run in parallel to get to the best possible design for the contrstraints as soon as possible. This allowed many combinations and configurations of wing elements to be tested and simulated.
The assement was to be carried out using the latest Computational Fluid Dynamics (CFD) software to simulate the conditions during straight line acceleration and cornering. This was to be done by carefully simulating the 2D aerofoil shape of wing elements to find the best configuration, and then using that to create 3D Solidworks CAD models with the same cross section for the wing elements as the aerofoil. The CAD models are then used for fluid flow simulations in ANSYS Fluent to generate the simulated drag and downforce levels, as well as other key metrics. The model was placed in a virtual wind tunnel where flow was simulated at 14m/s and allowed to fully develop before coming into contact with the wing surface.The fluid flow use the Realizable K-Epsilon for turbulence modelling due to its accuracy in this application, as it takes turbulent viscosity (Cu) into account as a variable rather than a constant.