Search Results

Comparability of measured aerodynamic properties is important in the car industry. The understanding of test section interference is a key factor when testing ground vehicles in different wind tunnels. Special publications (SP) on this topic were prepared by SAE sub-committees in the past, where both closed wall and open jet test sections were covered. Although the information in these SP's is not outdated, a lot of new investigations have contributed to the existing knowledge. The aim of this paper is to give a brief survey of the available new literature, which was published afterwards. In order to give easy access to the information, the new literature is clustered in the paper according to the different approaches to the analysis of test section interference. The available benchmark data is ordered according to their origin (full scale, model scale, CFD).

Audi's new full scale aeroacoustic wind tunnel is under full operation now. The new facility is designed for full scale automotive testing of aerodynamics and aeroacoustics for vehicles up to 3 m2 frontal area at wind speeds up to 300 kph. The highlights are the unique ground simulation system with boundary layer suction and a 5-belt-system, and the extremely low background noise of only 60 dB(A) at 160 kph. First the background of the project is illustrated and the need for the special features of the tunnel is deduced form the industrial requirements. Then an overview of the facility design is given with a detailed description of the key technical components. The calibration of the self-correcting test section will be discussed and the physical background for it will be examined more closely. For the calibrated wind tunnel the results of two correlation tests including open jet as well as closed wall wind tunnels show a reasonable conformity.