The Interior Design of a 40% Scaled DrivAer Body and First Experimental Results

This report addresses the interior design of a 40% scaled wind tunnel model of a generic medium-sized car geometry — the so-called DrivAer body. The model was designed for being investigated inside the wind tunnel facility at the Technische Universität München, which was recently upgraded by a single-belt ground simulation system. The wind tunnel model is very modular: it features several exchangeable parts, such as three exchangeable rear ends, three different underbody configurations, and different wheel rim geometries. In addition to this, the engine compartment is equipped with a model heat exchanger to adjust the mass flow rate through the underhood area. Apart from the model itself, we would also like to introduce some of the measurement equipment that we used during our wind tunnel tests, for example a set of five independent force balances. Furthermore, a method to account for the falsifying rolling resistance of the wheels is shown. Finally, results of experiments to determine the aerodynamic drag generated at the front and the rear axes of the vehicle will be discussed and a small data base of drag values for various vehicle configurations will be provided.