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Aeroacoustics is playing an increasing role in the development of new passenger cars. However, most existing wind tunnels, with few recent exceptions, have been designed and built with little or no attention to their aeroacoustic aspects. Building new wind tunnels with excellent low noise levels is technically feasible today, however it is not often justifiable from an economic standpoint. In the case of the Pininfarina wind tunnel, built in 1972 without any specific noise target, a decision was taken in 1984 to progressively upgrade the facility and the acoustic measuring techniques. A target of reaching a background noise level low enough to allow satisfactory acoustic development work on new cars, with the contemporary use of more modern measuring techniques, was established. This decision implicitly assumed that, to do this development work, it is not necessary to reach the very low noise levels of a pure acoustic wind tunnel.

Particle Image Velocimetry (PIV) is a recent measuring technique, which has been used up to now mainly by University Laboratories in small-scale wind tunnels and by Aeronautical Research Centers in small and large facilities. Its use in full-scale automotive testing is not common. It is not so easy, often rather difficult, due to a number of problems, sometimes of practical nature, sometime caused by technology limitations. This paper reports the results of some tests, carried out by CIRA (Centro Italiano Ricerche Aerospaziali) in the Pininfarina wind tunnel on a full-scale car, in the frame of the European Thematic Network “PIVNET”. A description of the test set up, of the instrumentation used for these tests, as well as an analysis of the advantages provided by this technique and of its present limitations, are reported. During the tests, in order to outline the potential of this measuring technique, some specific areas of the car flow field, have been investigated.