In F-1 race car aerodynamics, it is essential to create considerable downforce to provide good traction for faster acceleration, braking and cornering. In recent years, innovative trailing-edge serrations have been used in the rear wings of Formula One teams (Mercedes, McLaren, Ferrari, Williams, and Renault) to improve the aerodynamic performance of the multi-slotted flap system. The serrations create high-energy, mini vortices passing over the top and lower surfaces of the flap. The serrations can re-energise the boundary layer, delaying separation on the flap and increasing the lift coefficient. In addition, race teams applied serrations to DRS (Drag Reduction System) and gurney flaps.
Serrations are commonly used in the leading and trailing edges of wind turbine blades to reduce noises. The idea of serrations originated from the biomimicry of the silent wings of owls. Their feather structures are similar to serrations responsible for reducing noise generated by the turbulence eddies at the trailing edge. Bio-inspired serrations consist of two types: sinusoidal and sawtooth. Recent studies have focused mainly on the noise generation of trailing edge serrations in wind turbines (Juknevicius and Chong 2018, Thomaraeis and Papadakis, 2017). Currently, there are no published research results on the effectiveness of use serrations in complex multi-slotted wings commonly used in Formula 1 cars. Previous wind tunnel and numerical simulation studies on wind turbine aerofoils have demonstrated that the trailing edge serrations significantly increase lift coefficients with no significant drag rise (Liorente and Ragni, 2019).
This study investigates the aerodynamic performance of the serrations and topology of the mini vortices at the near wake region. The central research questions of the research are:
1) How do the mini-vortices generated by the serrations interact with the boundary layers on the flap surfaces in F-1 race cars?
2) What are the effects of the wavelength, amplitude, shape, and flap angle on the aerodynamics performance?
3) What is the aerodynamic performance of different configurations of serrations?
The research methods involve the use of Computational Fluid Dynamics (CFD) software and wind-tunnel studies of a simplified model of F-1 rear wing with serrations and a single slotted flap. The ANSYS software uses the finite-volume method to solve the time-averaged Navier Stokes equations using appropriate transitional or turbulence models. The turbulence models (Spalart-Allmaras, k-omega SST, Transition SST) can resolve time-average vortical structures at the wake of the serrations. The numerical simulation will obtain the lift and drag coefficients of various serration configurations and flap settings. The results can be compared with the wind tunnel testing results using a model manufactured at the University.
This study is important for two reasons:
1. At present, the mechanism of how the trailing-edge eddy structures interact with the flap to enhance boundary layer attachment at pre-stall and post-stall angles is not well understood.
2. The serration optimisation is very complex, depending on the precise serration configurations and flap setting. Most of the design process is based on trial and error. There is no published research literature on the application of serrations in racing sport due to commercial interests and competition among race teams.