Mass transfer in eddies close to air‐water interface

Abstract
Deterministic analyses applied to both velocity and concentration fluctuation data obtained in a region extremely close to air‐water interface in a free‐surface, unbaffled stirred tank allow estimation of the length and the velocity scales of individual eddies taking part in gas absorption. The mass transfer prediction by this method is superior to that by a statistical method using an integral length scale in the low‐turbulence flow employed in this work. Eddy velocities are generally lower in the diffusion boundary layer zone compared with the bulk zone. Small eddies are generally associated with low velocity scales whereas large eddies occur at high velocity scales. Local mass transfer coefficients are high in regions where small eddies are dominant.