On gas absorption into a turbulent liquid

Mass transfer across the surface of a turbulent flowing liquid is here assumed to be determined by relatively large scale eddies. Their length scale is taken to be the integral scale of the turbulence in the bulk of the fluid, while their intensity is also taken to correspond to that of the bulk turbulent flow field. Calculations have been carried out for a simple cellular model and have been compared with experimental results for absorption of CO2 into water in the flow behind a grip placed across the entrance to an open channel. Agreement has been remarkably good. It is emphasized that there are no free parameters in the model. The original objective of the work was to provide a model for the process of re-aeration of polluted rivers and streams.