SIMULTANEOUS PIV AND LIF EXPERIMENTS ON A ROUND JET IN COUNTERFLOW

In the present work Particle-image-velocimetry (PIV) and Laser-induced-fluorescence (LIF) have been simultaneously applied to the study of a round jet in a counterflowing stream. The aim of the study was, on one side, the investigation of the potentiality and the limits of this newly developed technique. On the other side, it was attempted to combine the information obtained with the two methods in order to contribute to the understanding of this complex flow phenomenon.
Instantaneous LIF images show a good correspondence with the vorticity structures obtained from PIV. By comparing the statistics of the results from the two methods a general agreement is observed, which however not always holds also in detail, and a relationship is proposed between concentration and velocity field.