High-resolution three-color PIV technique using a digital SLR camera

Particle image velocimetry (PIV) is used for measuring velocity distributions in planar cross sections of a fluid flow. The PIV technique is nonintrusive and not affected by variations in the fluid temperature. However, the velocity range and the accuracy of measurement are dependent on the spatial resolution of the camera. To overcome this limitation, a color digital single-lens reflex (SLR) camera and three illumination colors were used to simultaneously obtain two pairs of time delays. The three illumination colors, namely, red, green, and blue, were generated by diode lasers and had wavelengths of 650, 532, and 445 nm, respectively. Visualization images were obtained by a color digital SLR camera with color (red, green, and blue) pixel image grids. The uncertainty of the three-color PIV technique was evaluated using standard PIV images, and the technique was used to investigate the heat transfer and fluid flow characteristics of the natural convection produced by a vertical grooved panel heated on one side. The new color PIV technique was also used to measure a 3D velocity field by deforming the shape of the light sheet. The results confirmed the feasibility of using multiple cameras to develop a high-resolution 3D PIV system. © 2013 by Begell House, Inc.