Search Results

The Porsche 1:4-scale model wind tunnel was upgraded with a moving belt in combination with basic and distributed boundary layer suction devices. The belt is placed between the rotating wheels of the model with the external underfloor balance in operation. Special attention was given to providing a sufficient length of the belt with regard to road simulation for the aerodynamic optimization of race car models with their specific wake behavior. The boundary layer suction systems control the regions beyond the belt. Furthermore the balance was equipped with a pitch angle adjustment system in order to simulate the spring deflections of a moving vehicle. Results from a series of measurements taken from one race car model and one passenger car model are presented in order to investigate the influence of the boundary layer-, wheel rotation- and pitch adjustment-controls on the characteristic aerodynamic figures of the models.

For wind-tunnel measurements of drag and lift on passenger and racing-car models, correlations have been established between results obtained with a stationary ground-plane, with and without boundary-layer-suction, and a moving ground-plane. Compared with the stationary-ground-plane results without suction, the application of suction caused significant reductions in lift. These reductions were smaller, though, than those obtained with the moving-ground-plane, particularly in the case of rear-axle lift force. The influence of ground-plane suction on drag was also less than that of the moving ground-plane, which induced small drag increases.