Visualization of Three-Dimensional Vortical Structure of a Circular Jet

Abstract

The three-dimensional vortical structure of a circular water jet was investigated by a flow visualization technique. The jet was excited by axial and azimuthal perturbations to stabilize and enhance axisymmetric and streamwise vortices. A laser florescent dye and a laser light sheet were used to visualize the jet. The three-dimensional view of vortical structure was constructed by applying the Taylor hypothesis to the jet cross-sectional images. The view reveals the details of the complicated structure. From the three-dimensional view, the area of jet boundary surface was estimated to discuss jet mixing. The result suggests that the enhancement of axisymmetric and streamwise vortices is very effective to increase mixing.