Holographic PIV Technique

Holographic PIV (HPIV) is the most promising candidate for the next-generation velocimetry that can measure high spatial resolution instantaneous three-dimensional (3D) velocity fields. To explore the maximum performance capabilities of HPIV including spatial resolution, off-axis holography based HPIV has been our major direction of development. [see Holography and HPIV principle]

In the Laser Flow Diagnostics Lab (LFD), we have developed a fully automated off-axis HPIV system based on an injection-seeded dual-pulsed YAG laser and 3D data processing software. In our system, 90-degree particle scattering, dual reference beams, in situ reconstruction/data processing, and 3D velocity extraction based on a fast "Concise Cross Correlation" (CCC) algorithm are utilized. [see off-axis HPIV system]

The off-axis HPIV system has been tested for an acoustically excited air jet and the wake of a surface-mounted tab in a water channel flow, giving instantaneous 3D velocity fields for both flows. Experimental data of instantaneously measured 3D flow structures using this technique show great promise. This technique has also been applied to the measurement of particulate flow.