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This paper illustrates an advanced technique recently introduced in the Pininfarina wind tunnel for surveying the flow field of full-scale passenger cars. The technique is based upon the use of a non-nulling seven-hole probe, which is traversed continuously by a fast traversing system. The traversing system moves in the flow field under computer control. Planar surfaces of various preselected sizes can be surveyed with corresponding wind tunnel run times ranging from 5 to 40 minutes. As a result of a single planar survey, local pressures and velocities are mapped on a computer colour-display output. Usually, four colour maps are generated to show and summarize the distribution of total and static-pressure coefficients and total and cross-flow velocities. This technique is used mainly to investigate body wakes. Several examples regarding passenger cars or models, as well as an isolated formula-one type rear wing, are reported.

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.