Influence of jet exit conditions on mixing and statistics of flow fine structures

Mixing in a coaxial jet mixer was investigated at variable initial conditions simultaneously using PIV and PLIF methods. Velocity and concentration fields were measured at two spatial resolutions: across the mixer and in a small area at its axis resolving Kolmogorov's scale. Jet exit conditions were modeled by varying flow rate (3.10(3) <= Red <= 1.78.10(4)) and by applying vortex generators (tabs) at the jet exit. The study was executed within a transition flow region. Nevertheless, it is possible to claim that in the self-similarity flow region mean flow parameters do not depend on the initial conditions but turbulence does. The influence of the initial conditions is manifested in turbulent characteristics measured at a high spatial resolution and in the size of fine structures of the studied flows.