MASS TRANSFER ACROSS A SHEARED, WAVY AIR-WATER INTERFACE

The influence of surface motion on liquid phase controlled mass transfer is reviewed. The influence of surface waves and water drift current on air-water exchange was explored theoretically and experimentally, in a laboratory wind-wave facility. The results were analyzed by a surface renewal model. It was found that capillary waves contributed significantly to the enhancement of mass transfer rates at low water friction velocities (forUw* ≲ 1.5 cm s-1). At higher friction velocities, the rather spectacular increase in mass transfer was associated primarily with the turbulent water drift current. A convenient correlation is proposed for the liquid phase mass transfer coefficient with the water side friction velocity as the only hydrodynamic parameter. This correlation describes both laboratory and in situ data satisfactorily.