Visualized flow patterns of double concentric jets at low annulus velocities

Smoke-wire flow visualization helps analyze flow structures in the near wake region of unducted double concentric jets at low Reynolds numbers. The different jet velocities have different flow regimes in the near disk region. Experiments help analyze flow pattern, recirculation length and vortex shedding in each flow regime. Frequencies exhibit a correlation with the Strouhal number. Central-to-annular jet velocity ratio and various processes for vortex shedding are explained.