Study Of Open and Closed Wheels Aerodynamic Of Racing Cars in Wind Tunnels With Movable Ground At Different Car Speeds

摘要

The paper proposes the CFD study of a GT2 and a Fl racing car in a wind tunnel with movable ground and wheels. After a sensitivity analysis on the modelling of turbulence and the grid generation parameters, simulations are performed at different air speed to determine the pressure and shear contributions to the lift and drag coefficients. For the GT2 car, the drag and lift coefficients are around C_D=0.4 and C_L=-0.5 (down force). The down force is mostly the result of the under body diffuser and the rear wing. The rear wing contributes more than 85% of the lift force and 7-8% of the drag force. When reference is made to the low speed drag and lift coefficients, increasing the speed from 25 to 100 m/s produces an increase of C_D of more than 3 % and a reduction of C_L of more than 2 %. For the F1 car, the drag and lift coefficients are strongly variable in between race track and race track, mostly adjusted by the front and rear wing incidence. For the particular set-up, C_D is around 0.8 and C_L is around -1.2 (down force). The down force is mostly the result of the large front and rear wings immediately visible and the under body diffusers and vortex generators hidden below the car. These results suggest modifying the constant C_D and C_L values used in lap time simulation tools introducing the tabulated values to interpolate vs. the speed of the car.