Some issues on turbulent mixing and turbulence

Recent data on turbulent mixing suggest that the mixing transition, previously documented to occur in shear layers, also occurs in jets, as well as many other flows, and can be regarded as a universal phenomenon. The resulting, fully-developed turbulent flow requires a minimum Reynolds number of Re_T ≈ 10^4, or a Taylor Reynolds number of Re_T ≈ 10^2 to be sustained. Turbulent mixing in this fully-developed state does not appear to be universal, however, with a qualitatively different behavior between shear layers and jets.