Our understanding of the physical mechanisms at work in air-sea interaction remains elusive because of the formidable diffculties of obtaining and interpreting field observations from stationary and moving measurement platforms. From the perspective of the atmospheric boundary layer, questions persist as to the influence of ocean waves on the height of the wave induced boundary layer, the partitioning of the vertical momentum flux between turbulent and wave induced components, the modification of Monin-Obukhov similarity theory, the role wave age plays in the determination of surface drag, and the parameterization of wave effects for large scale numerical models.
Previously, we attempted to address some of these questions by incorporating wave effects into large-eddy simulations through simple linearized surface boundary conditions over idealized surface waves. These modeling efforts were not entirely satisfactory, since they were appropriate for very small wave slopes. In order to permit waves of realistic amplitude, we have modified our simulation techniques to allow moving curvilinear grids.
In this presentation, we will describe results from a series of direct and large-eddy numerical simulations of 3-d turbulent Couette flow over flat and time dependent sinusodial boundaries of finite amplitude. The wave effects will be illustrated by comparing mean profiles, statistical moments, wave induced fluxes, and surface drag for a range of wave age parameters. The changes to the turbulent flow structures will also be compared.