Simulation-Based Study of Wave Effects on Marine Atmospheric Boundary Layer

Abstract:

The interaction between ocean waves and turbulent winds plays an essential role in the dynamics of marine atmospheric boundary layer. The wave field consists of a wide range of wave components propagating in different directions with different speeds for different wavelengths. The long waves directly distort the wind field, while the short waves contribute significantly to the surface drag as surface roughness. In our study, we developed a two-way coupling numerical scheme for the simulation of wind and wave interaction. The turbulent wind field is computed using LES on wave-surface-fitted computational grid, and the wave field is computed with phase-resolved nonlinear wave simulation. At each time step, the wave simulation provides sea surface geometry and velocity as bottom boundary conditions to the wind simulation, while the latter provides wind forcing for the wave evolution. Our simulations with different wave scenarios, including a variety of windseas at different development stages, swells, and shoaling over bathymetry variations, show significant effects of waves on the wind field. Based on the simulation data, the momentum flux and turbulence transport processes in the lower marine atmospheric boundary layer are analyzed in detail with a focus on wave effects.