The Application of Particle Image Velocimetry in Automotive Aerodynamics. 2010-01-0120
Particle Image Velocimetry has developed over the last decade into a relatively mature flow-field measurement technique, capable of providing insight into time averaged and instantaneous flows that in the past have not been readily accessible. The application of the method in the measurement and analysis of flows around road vehicles has so far been limited to a relatively small number of specialist applications, but its use is expanding. This paper reviews the modern digital PIV technique placing emphasis on the important considerations required to obtain reliable and accurate data. This includes comments on each aspect of the PIV process, including initial setup and image acquisition, processing, validation and analysis.
A number of automotive case studies are presented covering different aspects of the method, including a diffuser exit flow, edge radius optimization, ‘A’ pillar flow and aerial wake flows. Results of the time-averaged and instantaneous vector fields are presented for each geometry along with their associated setup and processing. The example data is also used to determine the accuracy of time averaged velocity fields, and their related higher order statistics.
The results are discussed in respect of the additional insight that PIV provides in typical automotive flow-fields using advanced analysis techniques. Messages presented within the context of this paper are aimed at those in the automotive industry who are considering using PIV, or just beginning to employ PIV as a diagnostic tool to complement other techniques.