  The paper is devoted to two-phase flow simulations and investigates the
ability of a diffusive interface Cahn-Hilliard Volume-of-Fluid model to capture
the dynamics of the air-sea interface at geophysically relevant Reynolds
numbers. It employs a hybrid filtered/averaging Improved Detached Eddy
Simulation method to model turbulence, and utilizes a continuum model to
account for surface tension if the diffuse interface is under-resolved by the
grid. A numerical wind-wave tank is introduced to limit computational costs and
results obtained for two wind-wave conditions are analyzed in comparison to
experimental data at matched Reynolds numbers. The focus of the comparison is
on both time-averaged and wave-coherent quantities, and includes pressure,
velocity as well as modeled and resolved Reynolds stresses. In general,
numerical predictions agree well with the experimental measurements and
reproduce many wave-dependent flow features. Reynolds stresses near the water
surface are found to be especially important in modulating the critical layer
height. It is concluded that the diffusive interface approach proves to be a
promising method for future studies of air-sea interface dynamics in
geophysically relevant flows.
