This paper aims to provide a brief description on the aerodynamics development process of the new Nissan Qashqai using full-scale wind tunnel testing and Computational Fluid Dynamics simulations (CFD).
Aerodynamic drag reduction ideas were developed by means of numerical simulations with confirmation of the aerodynamics properties full-scale clay models were tested in the wind tunnel. Key aerodynamic features were developed including the optimization of hood and windscreen angle, roof camber, plan view corner radius, rear combination lamp with boundary layer trip edge and a large rear spoiler with incorporated winglet. The drag contribution of the under body was reduced by optimizing deflectors and panels. The A-pillar and door mirrors were designed to reduce drag and wind noise. Furthermore, the bumper opening area was optimized to balance the airflow for engine cooling and a low cooling drag contribution. In addition, an active grille shutter was developed to limit the amount of cooling airflow into the lower bumper opening to a minimum. Overall, the attention to details has lead to a class leading drag coefficient without compromising the styling scheme.
The final off-tool vehicle was tested in three different wind tunnels in order to investigate the effect of different ground simulations on the overall drag of the vehicle. Each wind tunnel had different ground simulation techniques including moving ground and rotating wheels, stationary ground with boundary layer suction and stationary ground without boundary layer treatment. The results will be discussed briefly in this paper.