Turbulence Structure and Scalar Transfer in Stratified Free-Surface Flows

Direct numerical simulations were used to investigate turbulence structure and scalar transfer across a shear-flee, nonwa y gas-liquid interface (flee surface) in stably stratified turbulent flows. These simulations solve the Nauier- Stokes and thermal-energy conservation equations, using a finite difference approximation. The relation between the turbulence structure in the stably stratified turbulent boundary layer and organized motion near the free surface are discussed. In addition, scalar transfer across a free suface is investigated by solving a passive scalar conservation equation after both uelocity and temperature fields are fully developed. The effects of stable stratification on the scalar transfer process in a region uely close to the flee surface are also discussed.

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