Triple-pulse Particle Image Velocimeter for the Simultaneous Measurement of the Velocity and Acceleration Fields of Fluid and Flexible Structure under

An advanced optical instrument is proposed with the capabilities of distinguishing between fluid and solid components of an image and measuring the velocity field and acceleration field of each. The design is based on the well known and robustly practiced principles of particle image velocimetry, but by introducing a third light pulse it produces a fundamental innovation that both enables the measurement of acceleration fields and improves the accuracy and spatial resolution of the velocity measurement. A prototype instrument will be constructed and tested in two flows fields having steady and unsteady accelerations using software that will be written as part of the development. The PIV interrogation analysis will implement a third order correlation method that has been shown to yield order of magnitude performance improvements over second order correlation, the long standing standard of PIV. The system is amenable to realization is a low cost design that eliminates lasers and expensive PIV cameras. Phase I development will demonstrate feasibility of image segmentation, triple pulse imaging, third order correlation and implementation of the software.