Digital particle image velocimetry system for real-time wind tunnel measurements

This paper describes a digital PIV system which is suitable for real-time acquisition and processing of planar velocity data in wind tunnels. After reviewing physical principals of PIV, some details of PIV hardware, programmable PIV processor, and software architecture are given, emphasizing the practical benefits of various features. This PIV system was used for studying the flowfield near the side of the body and aft of the wing flap of a 1:20 scale high wing transport with externally blown flaps (EBF) in a low speed wind tunnel facility having a 22 ft by 30 ft test section. A large data set of approximately six thousand vector maps, each having 47×29 2-D vectors, was recorded over three days. Preliminary flowfield measurements around an airplane model in a low speed wind tunnel are shown, including typical results showing velocity maps, and vorticity contours from the PIV data, and comparisons with five hole probe data from the same wind tunnel test