Single exposure double frame particle image velocimeters

Previous work on the optimization of particle image velocimeters for both double pulsed and multiple pulsed systems has been extended to single exposure, double pulsed systems in which cross-correlation methods replace direct autocorrelation methods. The spatial resolution, detection rate, accuracy and reliability of this system depend upon the same six non-dimensional parameters that were most significant in optimizing the PIV autocorrelation algorithm. They are the data validation criterion, the particle image density, the relative in-plane image displacement, the relative out-of-plane displacement, the velocity gradient and the ratio of the mean image diameter to the interrogation spot diameter. Previous comparisons to the method of analysis by Young's fringes are extended with the analysis being valid for both methods of PIV system interrogation. Recommendations for optimal system parameters are given for a range of velocity fields in order to minimize bias effects and loss of strength, for the direct cross correlation method for single exposure, double pulsed systems. Comparisons are made with direct autocorrelation methods for both double and triple pulsed systems.