On the small-scale statistics of turbulent mixing in electrochemical systems

Abstract Using the electrochemical method, measurements were made in a plane channel liquid flow, for which the Reynolds number ( Re  ≡  U  ∗  a / ν , U is the mean velocity and a is the hydraulic diameter) is variable between 3000 and 40,000. The Schmidt number of the salt (here, ferri-ferrocyanide) diffusing in water is typically about 1400, consequently the diffusion layer is located inside the viscous sublayer ( y + x parallel to the wall, the skewness factor of ∂ c ∂ x is about 1, independently on the Reynolds number. This property is very similar to that of a Pr  ∼ 1 passive scalar mixing in a sheared flow, already studied in the literature.