Aerodynamics and Aeroacoustics of Passenger Cars in a Controlled High Turbulence Flow: Some New Results

The new Turbulence Generation System (TGS), presented in the SAE papers 2003-01-0430 and 2004-01-0807, is now systematically used to get a deeper insight in the aerodynamic and aeroacoustic behavior of passenger cars in a controlled high turbulence flow. The TGS itself is used to generate a flow with characteristics more similar to those encountered by a car when traveling on the road, either for the presence of natural wind or for the presence of upstream vehicles.

A comparison is presented between tests performed in the low turbulence flow, i.e. base wind tunnel, and in the high turbulence flow, i.e. wind tunnel with TGS.

In particular, results regarding the following aspects are presented:

• Car Lift in the presence of various TGS setups;
• Brake Disk Cooling;
• Interior Noise.

For each one of these aspects, some time-averaged and some time-dependent values are presented.

The results of these investigations show that the traditional tests in a low-turbulence flow are not sufficient to thoroughly understand the aerodynamic and aeroacoustic behavior of road vehicles and that the results obtained in the controlled high turbulence regime are indeed necessary for the exhaustive car development.