Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Ivana Lučića 5, 10000 Zagreb, Croatia
Computational model was developed to investigate aerodynamic forces acting on a closed-wheel race car. A particular focus was on the effects of ground clearance and rake angle on aerodynamic drag and lift forces. Computations were performed for a steady viscous fluid flow using the realizable k-ε turbulence model and non-equilibrium wall functions. The computational results indicate a strong influence of ground clearance and rake angle on aerodynamic loading of a race car. The largest drag force coefficient was obtained for the largest ground clearance. The drag force coefficient for the squatting car is larger by 5% compared to the reference case, where the both front and rear ground clearances are 100 mm. For the nose-diving car, the drag force coefficient is equal to the reference case. Increasing the ground clearance caused a negligible increase in the lift force coefficient in comparison with the reference case. A decrease in the ground clearance yielded an increase in the lift force coefficient. The largest positive lift force coefficient was obtained for a squatting car, whereas the largest negative lift force coefficient was observed for a nose-diving car. While the favorable aerodynamic downforce acting on front wheels is larger for a nose-diving car, for rear wheels it is larger for a squatting car.