Measurements of a wall-bounded, turbulent, separated flow using HPIV

In this work, a lens-less, off-axis, holographic particle image velocimetry (HPIV) system is employed to investigate the separated flow over the blunt leading-edge of a flat plate. Multiple two-dimensional velocity maps withi n a three-dimensional region of interest (at a single instant in time) are obtained using a multigrid cross-correlation digital PIV technique. The out of plane vorticity is extracted from each of the velocity fields. An attem pt to determine the out of plane velocity for each image was also made usin g a stereoscopic scanner. However, owing to the small effective aperture of the holographic image it was not possible to stereoscopically measure the third component of velocity. The limitations of the stereoscopic scanning m ethod for HPIV and some potential solutions are discussed.