Computer simulation of turbulent mass transfer at a mobile interface

Abstract

Abstract Numerical solutions to the unaveraged mass balance equation for the case of a flat mobile interface reveal that both high‐ and low‐frequency velocity fluctuations can contribute to mass transfer. This is in contrast to transport to a solid boundary where only low‐frequency fluctuations, normal to the wall, are important. The average mass transfer coefficient is found to depend on Schmidt number to the −0.5 power, in agreement with classical theories. It is related to the velocity field in the liquid primarily through the mean‐square value of the gradient of normal velocity fluctuations at the interface.