Development and Initial Testing of a Full-Scale DrivAer Generic Realistic Wind Tunnel Correlation and Calibration Model

Wind tunnel testing is conducted to determine the aerodynamic characteristics of a vehicle under controlled and well-defined boundary conditions. Differences in wind tunnel facility layout, design, and subsequent onset flow conditions may result in differing aerodynamic conditions being attained for the same test property in different test facilities. Several OEMs develop vehicles in different regions and utilize local test facilities during the vehicle design process. Understanding the flow characteristics and correlations between test facilities is therefore essential to ensure that global processes can utilize data obtained in any region. Typically, automotive facility correlations are derived by evaluating a fleet of production level test properties in each facility. Adopting a test fleet approach for facility correlation yields three key issues; firstly, there are significant logistics and timing constraints. Secondly, over time the test fleet will deteriorate and potentially introduce random errors in the test data. Thirdly, test facility modifications may require repeat fleet assessments. This article aims to detail the development of a full-scale generic test property with the ability to better represent complex flow phenomena associated with road vehicles. Alternate rear-end geometries, permitting assessment of key flow phenomena associated with differing body styles, will be assessed using a single rolling chassis in six automotive wind tunnel facilities. Initial uncorrected results will be presented along with comparisons to the equivalent computational assessments for specific configurations. These initial results will then be summarized to show how Ford Motor Company plans to move forward with the experimental data. Finally, planned future work to ensure continual suitability of the test property as a reliable correlation and calibration tool in the automotive industry will be outlined.