Stereoscopic, Three-Dimensional PIV With Fuzzy Inference

An all-electronic digital particle-image velocimetry (PIV) system has been developed for use in measuring three-dimensional velocities at numerous points throughout a plane of interest in a supersonic flow. This system includes two high-resolution charge-coupled-device (CCD) video cameras oriented for stereoscopic imaging of the plane of interest. Two pulsed neodymium: yttrium aluminum garnet (Nd:YAG) lasers and associated optics illuminate the plane of interest with a sheet of light at two slightly different times to obtain double-exposure images of seed particles entrained in the flow. In principle, the velocity vector represented by the double-exposure image for each particle can be obtained by dividing the interexposure displacement vector by the interexposure time.