Aerodynamic Design and Wind Tunnel Testing of the RearEnd of a Formula Student Vehicle

Luís Miguel Poeiras Afonso

Key information

Authors:

Luís Miguel Poeiras Afonso (Luís Miguel Poeiras Afonso)

Supervisors:

Luís Rego da Cunha de Eça (Luís Rego da Cunha de Eça); André Calado Marta (André Calado Marta)

Published in

December 15, 2022

Abstract

The aerodynamics design among Formula Student teams has been seeing increasing complexity. Particularly for the FST Lisbon team, the design phase of new prototypes is currently revolving solely around CFD simulations. This work focus on improving the performance of the car and validating it through wind tunnel testing, to boost confidence in the obtained results and to pave the way for it to become a more broadly resorted procedure. By updating a lap simulator tool provided to predict the aerodynamic influence of the scores more accurately, the target was set to increase the downforce generated. An aerodynamic performance assessment was performed by analyzing the simulation data from the baseline design. The most critical regions identified were both lateral and back diffusers, and the rear wing. The lateral diffuser was the first to be redesigned and simulated. The large separation region previously identified was successfully mitigated while granting that no downforce was lost. The rear region was also modified by extending the monocoque and varying the diffuser profile yielding a 4.3% increase in downforce. This last design was scaled and 3D printed to be tested in the wind tunnel. Regarding the force measurements for slip angles of 0 and 4 degrees, the results stood very close to the predicted CFD simulations while the moments were substantially underestimated. However, the results for beta=10 degrees were considered unsatisfactory and the flow visualization via wool tufts, while capturing some important phenomena, has to be further improved. The redesign was validated in the wind tunnel.