Three-Dimensional Flow Visualization Using a Pulse Burst Laser System

Abstract

Further development of a high-speed three-dimensional flow visualization system is explored. The technique is based on the high-speed scanning and imaging of a laser sheet produced by a pulse burst laser capable of operating in excess of 1 MHz. The focus of this study is on the further development of the pulse burst laser, synchronization between the multiple system components, and data processing to yield 3-D images and high-quality 2-D images. Multiple 3-D visualizations (220 x 220 x 68 voxel resolution) of an acousticallyexcited jet are presented, each taken at “full-speed,” with the scanning mirror directing the laser through the flow, and the high-speed camera operating at 500,000 fps. In this configuration, each 3-D image took 136 μs to acquire. The presented visualizations demonstrate the ability of the technique to visualize complex, three-dimensional flow structures, such as ring vortices. Future work will concentrate on increasing laser intensity at shorter pulse durations to increase resolution and allow the technique to be used for supersonic flows.