Velocity and Vorticity Measurement in Flow Field Using Laser Tagging Method by Photochromic Dye

Abstract

A laser tagging method by photochromic dye was used to easily visualize detailed flow structures of creeping flow and liquid film jet. Excimer laser (248 nm) and Nd:YAG laser (355nm) were used to form dye traces in the flow tests and then observed by using a video camera. From the movement of the dye traces, velocity vector field was measured. Vorticity and divergence of velocity vector field were also calculated. As a result, it was confirmed that the laser tagging method by photochromic dye easily enabled the visualization of both flow tests.