Eduction of vortical structures by pressure measurements in noncircular jets

Vortical structures in the noncircular jets excited at the interaction mode were educed by measuring fluctuating static pressure, and their characteristics were discussed in relation to the mixing mechanism of the noncircular jets. The contours of phase-average fluctuating pressure show clearly the vortical structures of the noncircular jets, which compare reasonably with those observed by the flow visualization experiments. The evolution of the vortical structures is characterized by partial merging, stretching and splitting to smaller vortices. The effects of the noncircular vortical structures on mixing were also discussed based on the quantitative measurements of the velocity fields, the results suggesting that the interactions of vortical structures in the noncircular jets are very effective to enhance mixing.