A Three Dimensional Particle Image Velocimetry system and its application to the measurement of acoustic streaming

Abstract

A three-dimensional particle image velocimetry (3-D PIV) system has been developed, based on the concept of stereo-photography. A pulsed laser beam is used to illuminate a plane of light in the usual manner and this is photographed by a camera, adapted to form stereoscopic images by the addition of four mirrors, two placed in front of the camera and the other two between the lens and the film plane. With this arrangement two images are formed simultaneously, side-by-side on the film. The centre of each image is shifted laterally, as though the camera had taken each picture from a different position, but with the film and illumination planes remaining parallel in each case. Both halves of the film are analyzed as with standard particle image velocimetry (2-D PIV) and the resulting records are combined to give the three velocity components.