Direct numerical simulation of a turbulent shear flow beneath a wind-driven water surface

Abstract

Direct numerical simulation of a turbulent shear flow beneath a wind-driven water surface is performed to gain a better understanding of the hydrodynamic processes governing the vertical exchanges of heat and gases across the air-water interface. Coherent flow structures are identified which serve as the renewal eddies that pump the submerged fluids toward the water surface and bring down the upper fluids, and therefore enhance the scalar exchange between the air and the water body. The computed vertical distributions of the mean velocity, temperature and gas concentration compare well the parameterized profiles derived based on the surface renewal model.